Problem:
Kate rode her bicycle for 30 minutes at a speed of , then walked for 90 minutes at a speed of . What was her overall average speed in miles per hour?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Kate rode for 30 minutes hour at , so she rode 8 miles. She walked for 90 minutes hours at , so she walked 6 miles. Therefore she covered a total of 14 miles in 2 hours, so her average speed was .
The problems on this page are the property of the MAA's American Mathematics Competitions