¶ 2013 AMC8 Problem 11
Problem:
Ted's grandfather used his treadmill on days this week. He went miles each day. On Monday he jogged at a speed of miles per hour. He walked at the rate of miles per hour on Wednesday and at miles per hour on Friday. If Grandfather had always walked at miles per hour, he would have spent less time on the treadmill. How many minutes less?
Answer Choices:
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Solution:
Because time equals distance divided by rate, Grandfather was on the treadmill for hours or minutes on Monday. Similarly, he walked for hours, or minutes, on Wednesday and hours, or minutes, on Friday. The total time Grandfather spent on the treadmill was minutes. If he had walked the entire miles at miles per hour, he would have spent hours, or minutes, on the treadmill, so he would have saved minutes.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions