2022 AMC 10A Problem 2

Problem 2 of 25EasierAlgebra

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?

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Solution

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.

Concepts: ratio and proportion · estimation

Problem text and solution from the LIVE past-contest archive. See also the AoPS wiki page for community solutions.