A person travels a certain distance at 3 km/hr and reaches 15 mi late. If he travels at 4 km/hr reaches 15 min late. If he travels at 4 km/hr reaches 15 min earlier. The distance he has to travel is -
A
8.5 km
B
6 km
C
7.2 km
D
12 km
Correct Answer: 6 km
Let,Distance = x km ATQ, x3 - x4 = 12hours⇒4x - 3x12 = 12.'. x = 6