Q. A man can swim at the rate of 4 km/hr in still water. If the speed of the water is 2 km/hr, then the time taken by him to swim 10 km upstream is:
Answer:
$ 5 hrs$
Notes: $ \mathbf{5 hrs}$
Rate upstream = 4 – 2 = 2 km/hr
∴ Required Time $ = \frac{10}{2} = 5 hours$
Hence option [D] is correct answer.