Deck 4: Percents, Averages, and Estimates

Question 1

Carry the answer to two decimal places. An electrical supply uses the following wattages: 4,212 watts, 4,226 watts, 4,296 watts, 3,427 watts, 914 watts, 1,428 watts, and 4,293 watts. What is the average wattage used? Round the answer to the nearer hundredth.

Answer 1

3256.57

Question 2

Carry the answer to two decimal places. A contractor purchases quantities of wire, fittings, and switches listed at $2,150 at Successive trade discounts of 15%, 10%, and 3%. What is the net cost?

Answer 2

$1595.41

Question 3

Carry the answer to two decimal places. An electrician borrows $1,250 at 12.5% interest rate per annum to replace direct current motors with alternating current motors. The loan is paid back in 1 year and 2 months. Find the amount of interest.

Answer 3

$182.29

Question 4

Carry the answer to two decimal places. In replacing 55 lamp bulbs, an apprentice breaks 6. Find to the nearer hundredth percent the percent broken.

Question 5

Carry the answer to two decimal places. Solderless lugs are quoted at $42.50 less 40% for standard packages of 50. What will be the cost if only 22 are ordered at list price less 35%?

Question 6

Carry the answer to two decimal places. A 208-volt, 4-wire, 3-phase wye power system feeds a school building. Daily voltage readings taken for one week are 205.25 volts, 203.75 volts, 208 volts, 204.35 volts, 206.7 volts, 207 volts, and 208.55 volts. What is the average daily voltage of the system? Round the answer to the nearer hundredth.

Question 7

Carry the answer to two decimal places. Find, to the nearer hundredth horsepower, the amount of input horsepower required for the machine shown if it is to deliver an output of 97 horsepower.

Question 8

Carry the answer to two decimal places. What is the net price of a 2-pole, 100-ampere, 230-volt entrance switch if the list price is $137 with successive discounts of 35% and 3%?

Question 9

A contractor borrows $750 at 12% interest rate per annum and pays the debt 6 months later. What is the interest charged?

Question 10

Carry the answer to two decimal places. Workers receiving $124.60 per day have their wages increased by 8%. How much is received per day after the increase?

Question 11

Carry the answer to two decimal places. What is the net price of a 2-pole, 400-ampere, 230-volt enclosed entrance switch if it has a list price of $287 with successive discounts of 48% and 2%?

Question 12

Carry the answer to two decimal places. A contractors note, given 2 years 9 months ago for $856.25 and bearing an 8% interest rate per annum, is paid in full. What is the total amount of interest charged? Round to the correct cent.

Question 13

Carry the answer to two decimal places. An electrician borrows $2,750 at 9.7% interest rate per annum to purchase electrical supplies. If the loan is repaid in 15 months, how much is the interest?

Question 14

A shipment of 15 heat pumps arrives for storage at an electrical supply house. The pumps cannot be stacked, and each has a base measurement of 3.2 feet by 3.8 feet. A storage area 14 feet long and 12 feet wide is available. Is there sufficient space to store the shipment?

A) Yes
B) No

Question 15

Carry the answer to two decimal places. An electrician purchases 30 125-volt, 30-ampere, double-pole, doublebranch cutouts listed at $6.40 per box of 5, less 25%, and eight surface panels listed at $4.75 each, less 35%. Three percent is saved by paying the bill in 15 days. What is the cost if paid within 15 days?

Question 16

A 12-volt battery has had a capacity of 30 ampere-hour aging and has dropped to a capacity of 24 ampere-hours. Find the percent decrease in capacity.

Question 17

Carry the answer to two decimal places. Two-inch angle iron weighing approximately 2.97 pounds per foot is used to build panel-mounting racks. These amounts of iron are used: panel A, 9 feet; panel B, 10.75 feet; panel C, 8.6 feet; and panel D, 7.7 feet. What is the average weight per panel? Round the answer to the nearer hundredth.

Question 18

Carry the answer to two decimal places. Resistors R 1 and R 2 together use 63% of the total voltage. What is the voltage drop across resistor R 3 ?

Question 19

Carry the answer to two decimal places. A motor rated at 90 horsepower is actually developing 105 horsepower. What is the percent of horsepower overload?

Question 20

Carry the answer to two decimal places. Find the average of the following measurements: 17 inches, 16 inches, 18 inches, 21 inches, 29 inches, and 24 inches. Round the answer to the nearer hundredth.

Question 21

A contractor purchases motors listed at $6,800 and receives successive discounts of 20% and 10%. What is the net cost?

Question 22

A firm purchases several motors at a cost of $8,350 and gives a note bearing an 8% interest rate per annum. The note is due one year later. What is the total amount to be paid on the note?

Question 23

A contractor purchases a truck for $16,800 and is allowed $2,000 for trading in an old truck. A cash deposit of $200 is made. How much interest is paid for one year at a rate of 12% per annum?

Question 24

When mixing a quantity of electrolyte for a storage battery, the electrician uses 2 parts of acid and 3 parts of water. What percent is acid?

Question 25

An electrician purchases a new truck for the amount shown. He trades in an old truck and pays an amount of money in cash toward the total payment. When the loan is paid in full after one year, what will it cost in interest payments?

Question 26

If $168.00 is the profit on a job, and this represents 8% of the contract price, what is the contract price?