Digital PSAT Math Practice Question 259: Answer and Explanation

Question: 259

A bicyclist's distance in miles from her starting point can be modeled by the function d(x) = 16x, in which x is given in hours. What does the number 16 represent in this function?

• A. Her constant speed
• B. Her varying speed
• C. Her constant acceleration
• D. Her varying acceleration

Correct Answer: A

Explanation:

(A) Distance = (rate) × (time), so 16x must represent a rate multiplied by a time.

You're told that x is the time given in hours, so 16 must represent her rate. Rate is another word for speed, so you can narrow it down to choice (A) or choice (B). Because 16 is constant (not changing), the correct answer is choice (A).