Question : A man covers half part of a certain distance at 15 km/hr. He covers 40 percent of the remaining distance at the speed of 12 km/hr and covers the rest of the distance at the speed of 21 km/hr. What is his average speed for the entire journey?
Option 1:
Option 2:
Option 3:
Option 4:
Correct Answer:
Solution :
Let the total distance be
A man covers half part of a certain distance at 15 km/hr.
Time to cross half the distance =
He covers 40% of the remaining distance at the speed of 12 km/hr.
Time taken =
He covers the rest of the distance at the speed of 21 km/hr.
Time taken to cover the remaining distance =
So, the average speed
Hence, the correct answer is