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A man swims downstream a distance of 15 km in 1 hour. If the speed of the current is 5 km/ hour, the time taken by the man to swim the same distance upstream is
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- 1 hour 30 minutes
- 45 minutes
- 2 hours 30 minutes
- 3 hours
- 1 hour 30 minutes
Correct Option: D
Given , Distance travelled by man = 15 km
And speed of the current = 5 km/ hour
Let the speed of man in still water be y kmph.
| ∴ | = 1 | |
| y + 5 |
⇒ y + 5 = 15 ⇒ y = 10 kmph
| ∴ Time taken in swimming upstream = | = 3 hours | |
| 10 - 5 |
