A car moves a distance of 200m. It covers first half of the distance at speed 60 km per hour and the second half at speed v. If the average speed is 40 km per hour the value of v is
A car moves a distance of 200m. It covers first half of the distance at speed 60 km per hour and the second half at speed v. If the average speed is 40 km per hour the value of v is