1.  A boy goes to his school from his house at a speed of 3 km/hr and returns at a speed of 2 km/hr. If he takes 5 hours in going and coming, the distance between his house and school is :
A. 5 km
B. 5.5 km
C. 6 km
D. 6.5 km

Answer: Option C

Explanation:

Average speed = [(2 X 3 X 2) / (3 + 2) = 12/5 km/hr.

Distance travelled = (12 /5 X 5) km = 12 km.

∴ Distance between house and school :
     = 12/2 km = 6 km.