Problem:
One sunny day, Ling decided to take a hike in the mountains. She left her house at a.m., drove at a constant speed of miles per hour, and arrived at the hiking trail at a.m. After hiking for hours, Ling drove home at a constant speed of miles per hour. Which of the following graphs best illustrates the distance between Ling’s car and her house over the course of her trip?
Answer Choices:
A. 
B. 
C. 
D. 
E. 
Solution:
She drives miles per hour for the first hours, so she travels miles in the first two hours. This leaves choices , . Since she hikes for hours, she starts going back at PM. She drives miles at mph, so she gets back in hours, so she is back at .
Thus, the answer is .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions