Rajeev is trapped atop a building 200m high. He has with him a rope
150m long. There is a hook at the top where he stands. Looking
down, he notices that midway between him and the ground,at a
height of 100m, there is a ledge with another hook. In his pocket
lies a Swiss knife.
How might he be able to come down using the rope, the two hooks
and the Swiss knife?