Question

A boat travels 30 km upstream and 30 km downstream in 8 hours. Time taken for the same boat to travel 50 km downstream if its speed against the stream is 6 kmph.
1. 10 hours
2. 6 hours
3. 8 hours
4. 4 hours
5. 5 hours

Answer 1

Correct Answer - Option 5 : 5 hours

Given:

Speed of the boat against the stream = 6 kmph

Formula used:

Speed downstream = Speed of a boat in still water + speed of the stream

Speed upstream = Speed of a boat in still water - speed of the stream

Calculation:

Let downstream speed be A kmph.

⇒ 30/A + 30/6 = 8

⇒ A = 10 kmph

Speed of downstream of boat = 10 kmph

⇒ 50/10 hours = 5 hours

∴ Required time is 5 hours