A takes 2 hours 30 minutes more than B to walk 40 km. If A doubles his speed, then he can make it in 1 hour less than B. How much time ( in hours) does A require for walking a 40 km distance?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 7.
A takes 2 hours 30 minutes more than B to walk 40 km.
If A doubles his speed, then he can make it in 1 hour less than B.
Time = Distance/Speed
Let, Speed of A is x km/h.
Time taken by A to cover the distance = 40/x hour.
Time taken by B = (40/x) - 2.5 hours
When A doubles his speed time taken by A = 40/2x hour.
Accordingly -
[(40/x) - 2.5] - (40/2x) = 1
(40/x) - (40/2x) = 3.5
40/2x = 7/2
x = 40/7
Time taken by A to cover the distance = 40/(40/7) = 7 hours