Question

Travelling with a current, a boat covers a distance 1.5times greater than travelling 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