A man can row at 10 km/hr. in still water. If the velocity of current is 2 km/hr. and it takes him 10 hours to row to a place and come back, how far is the place?
36
24
48
56
Explanation:
Speed downstream = (10 + 2) = 12 km/hr.
Speed upstream = (10 - 2) = 8 km/hr
.Let the required distance be x km.
Then, x/12 + 1/8 = 10.
=> (2x+3x)/24 = 10.
=> 5x =10 $\times$ 24.
=> x = 48 km.