Problem:
Sam drove 96 miles in 90 minutes. His average speed during the first 30 minutes was (miles per hour), and his average speed during the second 30 minutes was . What was his average speed, in mph, during the last 30 minutes?
Answer Choices:
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B.
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E.
Solution:
Sam covered miles during the first 30 minutes and miles during the second 30 minutes, so he needed to cover miles during the last 30 minutes. Thus his average speed during the last 30 minutes was
The problems on this page are the property of the MAA's American Mathematics Competitions