A boat on a river travels 50 miles downstream in only 5 hours. It takes the same boat 9 hours to travel 18 miles upstream. What are the speed of the boat and the speed of the current?
A) Speed of boat: 4 miles per hour, speed of current: 6 miles per hour
B) Speed of boat: 9 miles per hour, speed of current: 5 miles per hour
C) Speed of boat: 6 miles per hour, speed of current: 4 miles per hour
D) Speed of boat: 5 miles per hour, speed of current: 5 miles per hour
E) Speed of boat: 8 miles per hour, speed of current: 5 miles per hour

Question

Quizplus · Accepted Answer

Let the speed of the boat be b and the speed of the current be c. Then we have the following system of equations:
b + c = 50/5 = 10
b - c = 18/9 = 2
Solving for b and c, we get b = 6 and c = 4. Therefore, the answer is choice C.

A Boat on a River Travels 50 Miles Downstream in Only