A kayaker can row 6 miles upstream, against a 2 mph current, in one hour more than he can row 7 miles downstream. What is his average speed in still water?
A) 3 mph
B) 5 mph
C) 6.5 mph
D) 8 mph

Question

Quizplus · Accepted Answer

The kayaker's speed in still water can be found by setting up equations based on the given information. Let $x$ be the kayaker's speed in still water. The time to row 6 miles upstream is $ \frac{6}{x-2} $ and the time to row 7 miles downstream is $ \frac{7}{x+2} $. According to the problem, $ \frac{6}{x-2} = \frac{7}{x+2} + 1 $. Solving this equation for $x$ gives $x = 5$ mph.

A Kayaker Can Row 6 Miles Upstream, Against a 2