Solve the problem.
-A boat can go 105 mph in still water. It takes as long to go 560 miles upstream as it does to go downstream 640 miles. How fast is the current?
A) 6 mph
B) 1 mph
C) 7 mph
D) 8 mph

Question

Quizplus · Accepted Answer

The speed of the boat in still water is 105 mph. Let the speed of the current be x mph. The effective speed upstream is (105 - x) mph, and downstream is (105 + x) mph. The time taken for both journeys is the same, so 560/(105 - x) = 640/(105 + x). Solving this equation gives x = 7 mph.

Solve the Problem. -A Boat Can Go 105 Mph in Still Water. It