Question

The speed of a boat in still water is 25 kmph and the speed of the stream is 5 kmph. Find the time taken by the boat to travel 10 km in the upstream direction.
1. 30 mins
2. 35 mins
3. 40 mins
4. 15 mins
5. 20 mins

Answer 1

Correct Answer - Option 1 : 30 mins

Given:

The speed of a boat in still water is 25 kmph

The speed of the stream is 5 kmph

Concept Used:

Speed of a boat in an upstream direction,

⇒ Speed of a boat in still water – Speed of stream

Speed = Distance/Time

Calculation:

Speed of a boat in an upstream direction,

⇒ 25 – 5

⇒ 20 kmph

Speed = Distance/Time

⇒ 20 kmph = 10/Time 

⇒ Time = 10/20

⇒ Time = 1/2 hour

⇒ Time = 30 mins

∴ The time taken to cover 10 km distance is 30 mins.

Speed of a boat in a downward direction,

⇒ Speed of a boat in still water + Speed of stream