Question

A man can row a boat at 8kmph in still water. If speed of the river is 2kmph, it takes him 48 minutes to row to a place and come back. how far is the place from the starting point?

Answer 1

If the river is moving along the direction of motion, then total speed v = vb + vr = 10km/h.
As we know that s = vt. Putting the values, we get:
S = 10km/h X 0.8h
=> S = 8Km is the answer.

If the river is moving in opposite direction to the motion of boat, then total speed v = vb – vr = 6km/h.
As s = vt. Putting the values, we get:
S = 6km/h X 0.8h
=> S = 4.8Km is the answer.