Question

A person travels in a car from his village to a town at a speed of 50 km/hr for 4 hours. There he spends an hour moving about 20 km. He then returns to his vilage at a speed 40 km/hr. His average speed over the whole journey (in km/hr) is

• A. 44
• B. 42
• C. $44\frac{4}{9}$
• D. $46\frac{2}{3}$

Answer 1

The correct option is B 42

We know that $Distance=Speed\times Time$
So the distance from village to town $=50\times 4=200km$
As the same distance is covered from the town back to the village, time taken $=\frac{Distance}{Speed}=\frac{200}{40}=5$ hours.
Now, Average Speed $=\frac{\text{Total distance covered}}{\text{total time taken}}=\frac{200+20+200}{4+1+5}=\frac{420}{10}=42km/hr$