1. A compressed air system consists of a compressor and receiver, 1500 ft of 4-in pipe, two gate valves, six standard elbows, and a manifold. Four rock drills requiring 200 cu-ft/min each are connected to the manifold by 1.25-in hoses 100 ft long. Pressure drop in the manifold is 3 psig and line leakage is 5%. Determine the pressure at the drill when all four drills are operating simultaneously and receiver pressure is 100 psig.