A man rows 20 km upstream and back again to the starting point in 110 minutes. If the speed of the stream is 2 kmph, then what is the speed of rowing in still water?

Name: A man rows 20 km upstream and back again to the starting point in 110 minutes. If the speed of the stream is 2 kmph, then what is the speed of rowing in still water?
Uploaded: 2026-01-30T12:33:09.374723+05:30
Duration: 4 min 1 s
Description: A man rows 20 km upstream and back again to the starting point in 110 minutes. If the speed of the stream is 2 kmph, then what is the speed of rowing in still water?

Solution

Total time taken in journey = 110 mins = $$\dfrac{\ 11}{6}$$ hrs

Total time = $$\dfrac{\ 20}{V\ +\ 2}+\dfrac{\ 20}{V\ -2}$$ = $$\dfrac{\ 11}{6}$$ hrs

$$\dfrac{\ 11}{120}=\dfrac{\ 2V}{V^2-4}$$

$$11(V^2)-44=240(V)$$
$$11(V^2)-240(V)-44=0$$

Therefore, V = 22 kmph.