PSAT Math Multiple-Choice Question 375: Answer and Explanation

Question: 375

An average consumer car can travel 120 miles per hour under controlled conditions. An average race car can travel 210 miles per hour. How many more miles can the race car travel in 30 seconds than the consumer car?

• A.
• B. 1
• C.
• D. 45

Correct Answer: A

Explanation:

A

Difficulty: Medium

Category: Unit Conversion

Getting to the Answer: Let the units in this question guide you to the solution. The speeds of the cars are given in miles per hour, but the question asks about the number of miles each car can travel in 30 seconds, so convert miles per hour to miles per second and then multiply by 30 seconds. The difference in speeds between the two vehicles is 210 - 120 = 90 miles per hour. Now, set up a conversion:

The race car can travel miles farther in 30 seconds, so (A) is correct.