2022 AMC 10A Problem 2

Question

Mike cycled

15

laps in

57

minutes. Assume he cycled at a constant speed throughout. Approximately how many laps did he complete in the first

27

minutes?

5

7

9

11

13

Use a proportion because the speed is constant

Estimate only after forming the exact fraction

We can set up a proportion to solve this problem:

\dfrac{15}{57} = \dfrac{x}{27}.

Cross multiplying, we get

x = \dfrac{15}{57} \cdot 27 = \dfrac{135}{19} \approx 7.

Thus, B is the correct answer.

Problem 2 in other years