The speed of a boat in still water is 8 km/h, while it takes 2 hours for the boat to cover a distance of 20 km downstream. What is the speed (in km/h) of the stream?
- AOption (a)
2.5
- BOption (b)
1.75
- COption (c)
2
- DOption (d)
1.5
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Correct answer
2
Why this answer is correct
Given:
The speed of a boat in still water = 8 km/h
Time taken to cover 20 km downstream = 2 hours
Formula used:
Speed downstream = Speed of boat in still water + Speed of stream
Distance = Speed x Time
Calculation:
Speed downstream = Distance / Time
⇒ Speed downstream = 20 km / 2 h
⇒ Speed downstream = 10 km/h
Speed downstream = Speed of boat in still water + Speed of stream
⇒ 10 km/h = 8 km/h + Speed of stream
⇒ Speed of stream = 10 km/h - 8 km/h
⇒ Speed of stream = 2 km/h
∴ The correct answer is option (3).




















