SAT Math Multiple Choice Practice Question 89: Answer and Explanation

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Question: 89

1. A student walked at a rate of 10 feet per second for 2 seconds, then at 15 feet per second for 3 seconds. Her average speed, in feet per second, was

A. 12
B. 12.5
C. 13
D. 13.5
E. 14

Correct Answer: C


C. Average speed equals total distance divided by total time, not just the average of the two speeds. The student traveled 20 feet over the first 2 seconds and 45 feet over the next 3, which makes 65 feet ÷ 5 seconds, or 13 feet per second.

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