Question

A motor boat goes downstream and covers a distance in 4 hours while it covers
the same distance upstream in 5 hours. If the speed of the stream is 3 km/hr, find
the speed of the motor boat in still water.​

Answer 1

Step-by-step explanation:

Let the distance between two port be

′

x

′

km.

And speed of boat in still water be

′

S

′

km/hr.

According to question,

In downstream,

x=(S+2)x4 ........(1) as, (Distance= Speed x Time)

Similarly,

In upstream,

x=(S−2)x5 ........(2)

From (1) & (2),

(S+2)4=(S−2)5

=> 4S+8=5S−10

=> S=18 km/hr.