Problem:
Angelina drove at an average rate of and then stopped minutes for gas. After the stop, she drove at an average rate of . Altogether she drove in a total trip time of hours including the stop. Which equation could be used to solve for the time in hours that she drove before her stop?
Answer Choices:
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E.
Solution:
Angelina drove before she stopped. After her stop, she drove hours at an average rate of , so she covered in that time. Therefore . Note that .
The problems on this page are the property of the MAA's American Mathematics Competitions