A car driver travels from the plains to the hill station, which are 200 km apart at an average speed of 40 km / hr. In the return trip, he covers the same distance at an average speed of 20 km / hr. The average speed of the car over the entire distance of 400 km / hr. Choose the most appropriate option.
A) 22 km/hr	B) 28.56 km/hr	C) 26.67 km/hr	D) 30 km/hr	E) None
Sol.   Average speed = (2×40×20 / 40 + 60) km/hr   = (80/3)km/hr   = 26.67 km/hr.   Answer 26.67 km/hr
<result>C</result>
A car driver travels from the plains to the hill station, which are 200 km apart at an average speed of 40 km / hr. In the return trip, he covers the same distance at an average speed of 20 km / hr. The average speed of the car over the entire distance of 400 km / hr.