Deck 4: A Survey of Probability Concepts

Question 1

i. A probability is usually expressed as a decimal, such as 0.70 or 0.27, but it may be given as a fraction, such as 7/10 or 27/100. ii. The probability of 1 represents something that is certain to happen.
iii. The probability of 0 represents something that cannot happen.

A) (i), (ii) and (iii) are all correct statements
B) (i) is a correct statement but not (ii) or (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Answer 1

(i), (ii) and (iii) are all correct statements

Question 2

i. The Cunard luxury liner, Queen Elizabeth 2, cannot be docked in Hong Kong and Bangkok at the same time. Events such as these that cannot occur simultaneously are said to be collectively exhaustive. ii. If there are 'm' ways of doing one thing and 'n' ways of doing another thing, the multiplication formula states that there are (m)(n) ways of doing both.
iii. A permutation is an arrangement of a set of objects in which there is an order from the first through the last.

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Answer 2

(ii) and, (iii) are correct statements but not (i).

Question 3

A sales representative calls on four hospitals in York Region. It is immaterial what order he calls on them. How many ways can he organize his calls?

A) 4
B) 24
C) 120
D) 37

Answer 3

24

Question 4

i. A probability is usually expressed as a decimal, such as 0.70 or 0.27, but it may be given as a fraction, such as 7/10 or 27/100. ii. The closer a probability is to 0, the more likely that an event will happen.
iii. The closer the probability is to 1.00, the more likely an event will not happen.

A) (i), (ii) and (iii) are all correct statements
B) (i) is a correct statement but not (ii) or (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 5

Consideration is being given to forming a Super Ten Basketball Conference. The top 10 university basketball teams in the country, based on past records, would be members of the Super Ten Conference. Each team would play every other team in the conference during the season and the team winning the most games would be declared the national champion. How many games would the conference commissioner have to schedule each year? (Remember, McMaster versus Alberta is the same as Alberta versus McMaster.)

A) 45
B) 50
C) 125
D) 14

Question 6

A rug manufacturer has decided to use 7 compatible colours in her rugs. However, in weaving a rug, only 5 spindles can be used. In advertising, the rug manufacturer wants to indicate the number of different colour groupings for sale. How many colour groupings using the seven colours taken five at a time are there? (This assumes that 5 different colours will go into each rug, i.e., there are no repetitions of colour.)

A) 120
B) 2,520
C) 6,740
D) 36

Question 7

i. The Cunard luxury liner, Queen Elizabeth 2, cannot be docked in Hong Kong and Bangkok at the same time. Events such as these that cannot occur simultaneously are said to be mutually exclusive. ii. If there are 'm' ways of doing one thing and 'n' ways of doing another thing, the multiplication formula states that there are (m) $\bullet$ (n) ways of doing both.
iii. A permutation is an arrangement of a set of objects in which order does not matter.

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 8

You have the assignment of designing colour codes for different parts. Three colours are to be used on each part, but a combination of three colours used for one part cannot be rearranged and used to identify a different part. This means that if green, yellow and violet were used to identify a camshaft, yellow, violet and green (or any other combination of these three colours) could not be used to identify a pinion gear. If there are 35 combinations, how many colours were available?

A) 5
B) 7
C) 9
D) 11

Question 9

i. A probability is usually expressed as a decimal, such as 0.70 or 0.27, but it may be given as a fraction, such as 7/10 or 27/100. ii. The closer a probability is to 0, the more likely that an event will not happen.
iii. The closer the probability is to 1.00, the more likely an event will happen.

A) (i), (ii) and (iii) are all correct statements
B) (i) is a correct statement but not (ii) or (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 10

An electronics firm manufactures three models of stereo receivers, two cassette decks, four speakers and three CD players. When the four types of components are sold together, they form a "system." How many different systems can the electronic firm offer?

A) 36
B) 18
C) 72
D) 144

Question 11

The numbers 0 through 9 are to be used in code groups of four to identify an item of clothing. Code 1083 might identify a blue blouse, size medium. The code group 2031 might identify a pair of pants, size 18, and so on. Repetitions of numbers are not permitted, i.e., the same number cannot be used more than once in a total sequence. As examples, 2256, 2562 or 5559 would not be permitted. How many different code groups can be designed?

A) 5,040
B) 620
C) 10,200
D) 120

Question 12

i. The probability of an event, based on a classical approach, is defined as the number of favourable outcomes divided by the total number of possible outcomes. ii. If among several events only one can occur at a time, we refer to these events as being mutually exclusive events.
iii. The probability of rolling a 3 or 2 on a single die is an example of conditional probability.

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 13

Six basic colours are to be used in decorating a new condominium. They are to be applied to a unit in groups of four colours. One unit might have gold as the principal colour, blue as a complementary colour, red as the accent colour and touches of white. Another unit might have blue as the principal colour, white as the complimentary colour, gold as the accent colour and touches of red. If repetitions are not permitted, how many different units can be decorated?

A) 360
B) 25
C) 125
D) 1,296

Question 14

i. An illustration of an experiment is turning the ignition key of an automobile as it comes off the assembly line to determine whether or not the engine will start. ii. If there are 'm' ways of doing one thing and 'n' ways of doing another thing, the multiplication formula states that there are (m)*(n) ways of doing both.
iii. A permutation is an arrangement of a set of objects in which there is an order from the first through the last.

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 15

What does equal?

A) 640
B) 36
C) 10
D) 120

Question 16

A builder has agreed not to erect all "lookalike" homes in a new subdivision. Five exterior designs are offered to potential homebuyers. The builder has standardized three interior plans that can be incorporated in any of the five exteriors. How many different ways are the exterior and interior plans offered to potential homebuyers?

A) 8
B) 10
C) 15
D) 30

Question 17

i. An experiment is an activity that is either observed or measured. ii. If an experiment, such as a die-tossing experiment, has a set of events that includes every possible outcome, the set of events is called collectively exhaustive.
iii. The combination formula is: n!/(n - r)!

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 18

Six basic colours are to be used in decorating a new condominium. They are to be applied to a unit in groups of four colours. One unit might have gold as the principal colour, blue as a complementary colour, red as the accent colour and touches of white. Another unit might have blue as the principal colour, white as the complimentary colour, gold as the accent colour and touches of red. If repetitions are permitted, how many different units can be decorated?

A) 7,825
B) 24
C) 125
D) 1,296

Question 19

There are two letters C and D. If repetitions such as CC are permitted, how many permutations are possible?

A) 1
B) 0
C) 4
D) 8

Question 20

i. A subjective probability can be assigned to an event by an individual based on the individual's knowledge about the event. ii. The probability that you would assign to the likelihood that the Hamilton Tiger Cats will be in the Grey Cup this season must be between 0 and 10.
iii. A probability is a number from -1 to +1 inclusive that measures one's belief that an event resulting from an experiment will occur.

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 21

The machine has just been filled with 50 black, 150 white, 100 red and 100 yellow gum balls that have been thoroughly mixed. Sue and Jim approached the machine first. They both said they wanted red gum balls. What is the likelihood they will get their wish?

A) 0.50
B) 0.062
C) 0.33
D) 0.75

Question 22

The National Centre for Health Statistics reported that of every 883 deaths in recent years, 24 resulted from an automobile accident, 182 from cancer and 333 from heart disease. Using the relative frequency approach, what is the probability that a particular death is due to an automobile accident?

A) 24/883 or 0.027
B) 539/883 or 0.610
C) 24/333 or 0.072
D) 182/883 or 0.206

Question 23

A lamp manufacturer has developed five lamp bases and four lampshades that could be used together. How many different arrangements of base and shade can be offered?

A) 5
B) 10
C) 15
D) 20

Question 24

The first card selected from a standard 52-card deck was a king. If it is returned to the deck, what is the probability that a king will be drawn on the second selection?

A) 1/4 or 0.25
B) 1/13 or 0.077
C) 12/13 or 0.923
D) 1/3 or 0.33

Question 25

A group of employees of Unique Services is to be surveyed with respect to a new pension plan. In-depth interviews are to be conducted with each employee selected in the sample. The employees are classified as follows. What is the probability that the first person selected is classified as a maintenance employee?

A) 0.20
B) 0.50
C) 0.025
D) 1.00

Question 26

A study of 200 stamping firms revealed these incomes after taxes: What is the probability that a particular firm selected has $1 million or more in income after taxes?

A) 0.00
B) 0.25
C) 0.49
D) 0.51

Question 27

When two or more events can occur concurrently it is called

A) conditional probability.
B) empirical probability.
C) joint probability.
D) a tree diagram.

Question 28

A survey of top executives revealed that 35% of them regularly read Time magazine, 20% read Newsweek and 40% read Macleans & World Report. Ten percent read both Time and Macleans. What is the probability that a particular top executive reads either Time or Macleans regularly?

A) 0.85
B) 0.06
C) 1.00
D) 0.65

Question 29

The result of a particular experiment is called a(n)

A) observation.
B) conditional probability.
C) event.
D) outcome.

Question 30

A board of directors consists of eight men and four women. A four-member search committee is to be chosen at random to recommend a new company president. What is the probability that all four members of the search committee will be women?

A) 1/120 or 0.00083
B) 1/16 or 0.0625
C) 1/8 or 0.125
D) 1/495 or 0.002

Question 31

Routine physical examinations are conducted annually as part of a health service program for the employees. It was discovered that 8% of the employees needed corrective shoes, 15% needed major dental work and 3% needed both corrective shoes and major dental work. What is the probability that an employee selected at random will need either corrective shoes or major dental work?

A) 0.20
B) 0.25
C) 0.50
D) 1.00

Question 32

Giorgio offers the person who purchases a 250 ml bottle of Allure two free gifts, either an umbrella, a 30 ml bottle of Midnight, a feminine shaving kit, a raincoat or a pair of rain boots. If you purchased Allure what is the probability you selected at random an umbrella and a shaving kit in that order?

A) 0.00
B) 1.00
C) 0.05
D) 0.20

Question 33

There are 10 rolls of film in a box and 3 are defective. Two rolls are to be selected one after the other. What is the probability of selecting a defective roll followed by another defective roll?

A) 1/2 or 0.50
B) 1/4 or 0.25
C) 1/120, or about 0.0083
D) 1/15, or about 0.07

Question 34

i. The complement rule states that the probability of an event not occurring is equal to one minus the probability of its occurrence. ii. If there are two independent events A and B, the probability that A and x B will occur is found by multiplying the two probabilities. Thus for two events A and B, the special rule of multiplication shown symbolically is: P(A and B) = P(A) P(B).
iii. The general rule of multiplication is used to find the joint probability that two events will occur. Symbolically, the joint probability P(A and B) is found by: P(A and B) = P(A)P(B/A).

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 35

When an event's probability depends on the likelihood of another event, the probability is

A) conditional probability.
B) empirical probability.
C) joint probability.
D) Mutually exclusive probability.

Question 36

Which approach to probability is exemplified by the following formula?

A) Classical approach
B) Empirical approach
C) Subjective approach

Question 37

According to which classification or type of probability are the events equally likely?

A) Classical
B) Empirical
C) Subjective
D) Mutually exclusive

Question 38

What does the complement rule state?

A) P(A) = P(A) -P(B)
B) P(A) = 1 -P (not A)
C) P(A) = P(A) $\bullet$ P(B)
D) P(A) = P(A)X + P(B)

Question 39

When are two events mutually exclusive?

A) They overlap on a Venn diagram
B) If one event occurs, then the other cannot
C) Probability of one affects the probability of the other
D) They both happen at the same time

Question 40

When an experiment is conducted "without replacement",

A) events are independent
B) events are equally likely
C) the experiment can be illustrated with a Venn Diagram
D) the probability of two or more events is computed as a joint probability

Question 41

Three defective electric toothbrushes were accidentally shipped to a drugstore by the manufacturer along with 17 non-defective ones. What is the probability that the first two electric toothbrushes sold will be returned to the drugstore because they are defective?

A) 3/20 or 0.15
B) 3/17 or 0.176
C) 1/4 or 0.25
D) 3/190 or 0.01579

Question 42

Each salesperson in a large department store chain is rated with respect to sales potential for advancement. These traits for the 500 salespeople were cross classified into the following table. What is the probability that a salesperson selected at random has above average sales ability and is an excellent potential for advancement?

A) 0.20
B) 0.50
C) 0.27
D) 0.75

Question 43

A study of the opinion of designers with respect to the primary colour most desirable for use in executive offices showed that: What is the probability that a designer does not prefer red?

A) 1.00
B) 0.77
C) 0.73
D) 0.23

Question 44

A group of employees of Unique Services is to be surveyed with respect to a new pension plan. In-depth interviews are to be conducted with each employee selected in the sample. The employees are classified as follows. What is the probability that the first person selected is in management and in supervision?

A) 0.00
B) 0.06
C) 0.15
D) 0.21

Question 45

A group of employees of Unique Services is to be surveyed with respect to a new pension plan. In-depth interviews are to be conducted with each employee selected in the sample. The employees are classified as follows. What is the probability that the first person selected is either in maintenance or in secretarial?

A) 0.200
B) 0.015
C) 0.059
D) 0.001

Question 46

A study of the opinion of designers with respect to the primary colour most desirable for use in executive offices showed that: What is the probability that a designer does not prefer yellow?

A) 0.000
B) 0.765
C) 0.885
D) 1.000

Question 47

If two events are independent, then their joint probability is

A) computed with the special rule of addition
B) computed with the special rule of multiplication
C) computed with the general rule of multiplication
D) computed with Bayes theorem

Question 48

i. A coin is tossed four times. The probability is ¼ or 0.25 that all four tosses will result in a head face up. ii. A coin is tossed four times. The probability is 1/8 or 0.125 that all four tosses will result in a head face up.
iii. If two events are mutually exclusive, then P(A or B) = P(A)P(B).

A) (i), (ii) and (iii) are all correct statements
B) (i) and, (ii) are correct statements but not (iii).
C) (i) and, (iii) are correct statements but not (ii).
D) (ii) and, (iii) are correct statements but not (i).
E) (i), (ii) and (iii) are all false statements.

Question 49

A study by Tourism Ontario revealed that 50% of the vacationers going to Toronto visit the CN Tower, 40% visit SkyDome and 35% visit both. What is the probability that a vacationer will visit at least one of these magnificent attractions?

A) 0.95
B) 0.35
C) 0.55
D) 0.05

Question 50

Each salesperson in a large department store chain is rated with respect to sales potential for advancement. These traits for the 500 salespeople were cross classified into the following table. What is the probability that a salesperson selected at random will have below average sales ability and fair potential for advancement?

A) 0.032
B) 0.10
C) 0.16
D) 0.32

Question 51

Each salesperson in a large department store chain is rated with respect to sales potential for advancement. These traits for the 500 salespeople were cross classified into the following table. What is the probability that a salesperson selected at random will have average sales ability and good potential for advancement?

A) 0.09
B) 0.12
C) 0.30
D) 0.525

Question 52

A group of employees of Unique Services is to be surveyed with respect to a new pension plan. In-depth interviews are to be conducted with each employee selected in the sample. The employees are classified as follows. What is the probability that the first person selected is a supervisor and in production?

A) 0.00
B) 0.06
C) 0.15
D) 0.21

Question 53

The following distribution table represents preferences for two types of cereals by 2,000 boys and girls. What is the probability that an individual, whether a boy or girl, prefers nutty cereal?

A) 500/1,000
B) 500/2,000
C) 1,200/2,000
D) 500/1,200
E) 800/2000

Question 54

A tire manufacturer advertises, "the median life of our new all-seasonradial tire is 120,000 km. An immediate adjustment will be made on any tire that does not last 120,000 km." You purchased four of these tires. What is the probability that all four tires will wear out before traveling 120,000 km?

A) 1/10 or 0.10
B) ¼ or 0.25
C) 1/64 or 0.0156
D) 1/16 or 0.0625

Question 55

An automatic machine inserts mixed vegetables into a plastic bag. Past experience revealed that some packages were underweight and some were overweight, but most of them had satisfactory weight. What is the probability of selecting and finding that all three of them are overweight?

A) 0.0000156
B) 0.0004218
C) 0.0000001
D) 0.075

Question 56

An automatic machine inserts mixed vegetables into a plastic bag. Past experience revealed that some packages were underweight and some were overweight, but most of them had satisfactory weight. What is the probability of selecting and finding that all three of them are satisfactory?

A) 0.900
B) 0.810
C) 0.729
D) 0.075

Question 57

The following distribution table represents preferences for two types of cereals by 2000 boys and girls. Find the probability that an individual selected at random will be a boy and prefer Fruity cereal.

A) 500/1,000
B) 500/2,000
C) 1,200/2,000
D) 500/1,200

Question 58

The following distribution table represents preferences for two types of cereals by 2,000 boys and girls. Find the probability that a person prefers Fruity cereal given that the person is a boy.

A) 500/1,000
B) 500/2,000
C) 1,200/2,000
D) 500/1,200

Question 59

A study of the opinion of designers with respect to the primary colour most desirable for use in executive offices showed that: What is the probability that a designer does not prefer blue?

A) 1.0000
B) 0.9075
C) 0.8850
D) 0.7725

Question 60

When applying the special rule of addition for mutually exclusive events, the joint probability is:

A) 1
B) 5
C) 0
D) 0.25
E) unknown

Question 61

A survey of 500 top Canadian companies reported what the companies' hiring outlook was for the next 18 months as well as the general company outlook for the economy over the same period of time. What is the probability that a randomly selected company from this sample does not have a favourable outlook for the economy over the next 18 months?

A) 325/500
B) 260/500
C) 175/500
D) 65/500

Question 62

Type of Attack Given that an assault victim is selected, what is the likelihood that the criminal is a stranger?

A) 757/2000
B) 1787/2000
C) 757/1426
D) 1426/2000

Question 63

A survey of 500 top Canadian companies reported what the companies' hiring outlook was for the next 18 months as well as the general company outlook for the economy over the same period of time. What is the probability that a randomly selected company does not plan to add jobs during the next 18 months?

A) 165/500
B) 335/500
C) 210/500
D) 25/500

Question 64

The following distribution table represents preferences for two types of cereals by 2000 boys and girls. Determine the probability that the person is a boy, given that the person likes Fruity Cereal.

A) 500/1,000
B) 500/2,000
C) 1,200/2,000
D) 500/1,200

Question 65

A survey of 500 top Canadian companies reported what the companies' hiring outlook was for the next 18 months as well as the general company outlook for the economy over the same period of time. Given that a randomly selected company has a favourable forecast, what is the probability that it plans to cut jobs during the next 18 months?

A) 25/500
B) 25/175
C) 125/175
D) 175/500

Question 66

The customer service department of H&R Block received a total of 235 telephone requests for a tip-sheet on personal tax or corporate tax. The following table summarizes callers' primary area of interest, and how they first heard about the tip-sheet. If one person is randomly selected, what is the likelihood that the caller first heard about the report from Television, given that the topic of interest is personal tax?

A) 40/235
B) 26/100
C) 20/100
D) 20/235

Question 67

A survey of 500 top Canadian companies reported what the companies' hiring outlook was for the next 18 months as well as the general company outlook for the economy over the same period of time. What is the probability that a randomly selected company has an unfavourable forecast for the economy for the next 18 months?

A) 25/500
B) 325/500
C) 65/500
D) 175/500

Question 68

An insurance company has collected the following data on the gender and marital status of 400 customers. Suppose that a customer is selected at random. Find the probability that the customer selected is married if the customer is female.

A) 125/240
B) 50/160
C) 110/160
D) 50/400

Question 69

Type of Attack What is the likelihood of a victim being attacked by a relative or acquaintance?

A) 389/505
B) 834/2000
C) 389/2000
D) 1166/2000

Question 70

A survey of 500 top Canadian companies reported what the companies' hiring outlook was for the next 18 months as well as the general company outlook for the economy over the same period of time. Given that a randomly selected company plans to add jobs during the next 18 months, what is the probability that they have an unfavourable outlook for the economy?

A) 325/500
B) 100/175
C) 175/500
D) 100/165
E) 15/165

Question 71

A survey of 500 top Canadian companies reported what the companies' hiring outlook was for the next 18 months as well as the general company outlook for the economy over the same period of time. Given that a randomly selected company plans to add jobs during the next 18 months, what is the probability that they have a favourable outlook for the economy?

A) 325/500
B) 165/500
C) 175/500
D) 235/500
E) 100/165

Question 72

Type of Attack Find the probability that when 1 of the 2000 subjects is randomly selected, the person chosen was robbed or was victimized by an acquaintance or relative.

A) 1223/2000
B) 903/1000
C) 1292/2000
D) 1234/2000

Question 73

Type of Attack If one person is randomly selected, what is the likelihood that he or she was victimized by a stranger, given that a robbery victim is selected?

A) 389/505
B) 389/1,118
C) 389/2,000
D) 1,234/2,000

Question 74

Type of Attack If one person is randomly selected, find the probability that they were victimized by a stranger.

A) 389/1166
B) 389/834
C) 1166/2000
D) 1234/2000

Question 75

An insurance company has collected the following data on the gender and marital status of 400 customers. Suppose that a customer is selected at random. Find the probability that the customer selected is married if the customer is male.

A) 125/240
B) 175/400
C) 125/175
D) 175/240

Question 76

An insurance company has collected the following data on the gender and marital status of 400 customers. Suppose that a customer is selected at random. Find the probability that the customer selected is not single.

A) 75/400
B) 175/400
C) 150/500
D) 325/500

Question 77

Each salesperson in a large department store chain is rated with respect to sales potential for advancement. These traits for the 500 salespeople were cross-classified into the following table: What is the probability that the selected salesperson has below average sales ability?

A) 50/500
B) 150/500
C) 300/500
D) 16/50
E) 154/500

Question 78

An insurance company has collected the following data on the gender and marital status of 400 customers. Suppose that a customer is selected at random. Is it more likely to be a single female or a single male? Determine the probabilities of each.

A) P(single male) = 25/240, P(single female) = 50/160, therefore more likely to be a single male
B) P(single male) = 25/400, P(single female) = 50/400, therefore more likely to be a single female.
C) P(single male) = 290/400, P(single female) = 185/400, therefore more likely to be a single male
D) P(single male) = P(single female) therefore equally likely

Question 79

Type of Attack If two different subjects are randomly selected, find the probability that they were both robbed.

A) 27.5%
B) 25.5%
C) 55%
D) 6.4%

Question 80

A survey of 500 top Canadian companies reported what the companies' hiring outlook was for the next 18 months as well as the general company outlook for the economy over the same period of time. What is the probability that a randomly selected company plans to cut jobs during the next 18 months?

A) 125/500
B) 375/500
C) 210/500
D) 25/500