Automobiles traveling on a road with a posted speed limit of 65 miles per hour are checked for speed by a state police radar system.The following table is a frequency distribution of speeds. What proportion of the cars traveled at least 55 but less than 65 miles per hour?
A) 0.33
B) 0.48
C) 0.56
D) 0.80

Question

Automobiles traveling on a road with a posted speed limit of 65 miles per hour are checked for speed by a state police radar system.The following table is a frequency distribution of speeds.  What proportion of the cars traveled at least 55 but less than 65 miles per hour?
A) 0.33 
B) 0.48 
C) 0.56 
D) 0.80

Quizplus · Accepted Answer

We need to sum up the frequencies of the speeds that are between 55 and 65 miles per hour, which are the speeds that satisfy the condition "at least 55 but less than 65."

These frequencies are: 40 + 28 + 15 = 83.

The total number of cars is 200.

Therefore, the proportion of cars that traveled at least 55 but less than 65 miles per hour is 83/200 = 0.415. However, this is not one of the answer choices.

We need to approximate this proportion to the nearest answer choice.

0.415 is between 0.33 (the lowest answer choice) and 0.48 (the next highest answer choice).

Since 0.415 is closer to 0.48 than to 0.33, the best choice is B: 0.48.

Automobiles Traveling on a Road with a Posted Speed Limit