Question

The time taken to travel a certain distance upstream is 17 hours. The speed of the boat in still water is 15 kms per hour. The time taken to travel the same distance downstream is 13 hours. Find the speed of the stream.
1. 1
2. 2
3. 3
4. 4

Answer 1

Correct Answer - Option 2 : 2

Given:

The time taken to travel a certain distance upstream is 17 hours. The speed of the boat in still water is 15 kms per hour. The time taken to travel the same distance downstream is 13 hours.

Formula:

Time taken by boat to travel upstream = D/(speed of bota in still water – speed of the stream)

Time taken by boat to travel downstream = D/(speed of bota in still water + speed of the stream)

Calculation:

let speed of stream be y

Distance in both the case is same

(15 – y) × 17 = (15 + y) × 13

⇒ 255 – 17y = 195 + 13y

⇒ 60 = 30y

⇒ Y = 2 kmph