¶ 1955 AHSME Problem 50
Problem: In order to pass going mph on a two-lane highway , going mph, must gain feet. Meantime, feet from , is headed toward him at mph. If and maintain their speeds, then, in order to pass safely, must increase his speed by.
Answer Choices:
A. 30 mph
B. 10 mph
C. 5 mph
D. 15 mph
E. 3 mph
Solution:
Let be the increase in the rate of and be the distance (in miles) travels to pass safely. The times traveled by and are equal:
Solve the second equation for miles.
Solve the first equation for .