1
There is a road beside a river. Two friends started from a place A, moved to a temple situated at another place B and then returned to A again. One of them moves on a cycle at a speed of 12 km/hr, while the other sails on a boat at a speed of 10 km/hr. If the river flows at the speed of 4 km/hr, which of the two friends will return to place A first (R.R.B. 2001)
Explanation:
Clearly, the cyclist moves both ways at a speed of 12 km / hr.

So, average speed of the cyclist = 12 km / hr.

The boat sailor moves downstream @ (10 + 4) i.e., 14 km / hr and upstream @ (10  4) i.e., 6 km / hr.



Since the average speed of the cyclist is greater, he will return to A first.
