I keep getting stuck on this resulted rates problem

A rope, attached to a weight, goes up through a pulley at the ceiling and back down to a worker, The worker holds the rope at the same height as the connection point between the rope and weight. The distance from the connection point to the ceiling is 30 ft. Suppose the worker stands directly next to th weight (i.e., a total rope length of 60 ft) and begins to walk away at a constant rate of 4 ft/s. How fast is the weight rising when the worker has walked: 10 feet? Answer 30 feet? Answer=