A man reaches his destination 40 minutes late if his speed is 3 km/hr, and reaches 30 minutes before time, if his speed is 4 km/hr. Find the distance of his destination from his starting point

Correct option is B

Given:
If man speed is 3km/hr he is 40 minutes late
If man speed is 4km/hr he is 30 minutes early
Formula Used:
Distance=Speed×Time
Solution:
Let the distance to school be D
Then time taken to reach school at 3km/hr =D/3
Time taken to reach school at 4 km/hr = D/4
Difference in time taken = D/3 - D/4 = 40+30 min
Converting minutes to hour
D/3 - D/4 = 70/60
(4D-3D)/12=7/6
D/12 =7/6
D= 12 ×7/6
D=14km