AMC 8 2006 Problem 3

AMC8 2006 年第 3 题

比与比例★★☆☆☆

Elisa swims laps in the pool. When she first started, she completed 10 laps in 25 minutes. Now she can finish 12 laps in 24 minutes. By how many minutes has she improved her lap time?

Elisa 在游泳池里游了几圈。当她第一次开始时，她在 25 分钟内完成了 10 圈。现在她可以在 24 分钟内游完 12 圈。那么她游一圈所花的时间减少了多少分钟？

A. $\displaystyle \frac{1}{2}$
B. $\displaystyle \frac{3}{4}$
C.1
D.2
E.3

正确答案 · Correct Answer

解析 · Solution

Solution 1

When Elisa started, she completed a lap in 25 10 = 2.5 10 25 =2.5 minutes. Now she can complete a lap in 24 12 = 2 12 24 =2 minutes. She has improved her lap time by 2.5 − 2 = 0.5 2.5−2=0.5 or 1 2 2 1 minute. Answer: 𝐴 A .

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