Question

Traveling with the current, a boat covers a distance 1.5 times greater than traveling against the current in the same amount of time. What is the speed of the boat in still water if the speed of the current is 1.5 mph?

Answer 1

Let the speed of the current equal c
and the speed of the boat in still water equal b.

b + c = 1.5 (b - c)
b + c = 1.5b - 1.5c
0.5b = 2.5c
b = 5c

The speed of the current is 1.5 mph so
b = 5 * 1.5 = 7.5 mph