A train cover a distance in 50 minutes, if it runs at a

A train cover a distance in 50 minutes, if it runs at a speed of 48 km per hour on an average. The speed at which the train must run to reduce the time of journey to 40 minutes ?

Total Distance = 48 x (50/60) km.
= 40 km

Required speed = [40 / (40/60)] km.
= (40 x 60 )/ 40 km/hr.
= 60 km/hr.