Question

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?

Answer 1

Clearly the cyclist moves both ways at a speed of 12 km/hr. 

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

So,average speed of the boat sailor=(2*14*6/14+6)km/hr =42/5 km/hr=8.4 km/hr. 

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