'K' cycled from A to B at 10 kmph and returned at the rate of 9 kmph. 'L' cycled both ways at 12 kmph. In the whole journey 'L' took 10 minutes less than 'K'. Find the distance between A and B ?

Let 'd' be the distance between A and B
K -time = d/10 + d/9 = 19d/90 hours
L -time = 2d/12 = d/6 hours
We know that, 10 min = 1/6 hours
Thus, time difference between K and L is given as 10 minutes.
=> 19d/90 - d/6 = 1/6
=> (19d-15d)/90 = 1/6
=> 4d/90 = 1/6
Thus,
d= 15/4 km = 3.75 km.

hence the distance between A and B is 3.75 km.