Kindly suggest easy method for solving the following question - The distance between a school and a playground is 10km, three friends starttravelling along a straight line from the school to playground such that two of them, A and B are travelling by cycle and the third, C starts walking. A drops B at a certain point along the way and goes back to pickup C. Meanwhile, B starts walking towards the playground as soon as A drops him, All three of them reach the playground at the same time. The speed of the cycle is 5 Kmph and the walking speed of any of the three friends is 2 Kmph. What is the distance walked by C?