Question

In a stream running at 2km ph, a motorboat goes 6 km ph upstream and back again to the starting point in 33 minutes. Find the speed of the motor boat in still water.

a) 20 km ph

b) 22 km ph

c) 24 km ph

d) 28 km ph

Answer 1

Correct option: b) 22 km ph

Explanation:

Let the speed of the motorboat in still water be x km ph speed downstream=(x+2) km ph; speed upstream=(x-2) km ph

(6/(x+2))+(6/(x-2)) =33/60 therefore x=22 km ph