Question:
Praful travels from P to Q at a speed of 50 km/hr and Q to P at a speed of 30 km/hr. Find the average speed for the whole journey?
A35 km/hr
B37.5 km/hr
C40 km/hr
D42 km/hr
Answer:
B. 37.5 km/hr
Explanation:
x=50 y=30 average speed=2xy/(x+y) =(2x50x30)/(50+30) = 37.5 km/hr