Solve.
-Bill can row 3 mph in still water. It takes him 3 hours 36 minutes to go 3 miles upstream and return. Find the speed of the current.
A)1.5 mph
B)3 mph
C)2.5 mph
D)2 mph

Question

Quizplus · Accepted Answer

The speed of the current is 2 mph. To solve this, let's denote the speed of the current as $c$ mph. The speed of the boat in still water is 3 mph, so the effective speed going upstream is $3 - c$ mph, and downstream is $3 + c$ mph. The distance each way is 3 miles, so the time to go upstream is $\frac{3}{3-c}$ hours, and downstream is $\frac{3}{3+c}$ hours. The total time is 3 hours and 36 minutes, which is 3.6 hours. Setting up the equation: $\frac{3}{3-c} + \frac{3}{3+c} = 3.6$. Solving this equation for $c$ gives $c = 2$ mph.

Solve. -Bill Can Row 3 Mph in Still Water. It Takes