A compressed air system consists of a compressor and receiver, 1500 ft (458 m) of 4-in. (10.2-cm) pipe, two gate valves, six standard elbows, and a manifold. Four rock drills requiring 200 cu ft/min (5.7 m3/min) each are connected to the manifold by 1-1⁄4-in. (3.2-cm) hoses 100 ft

(30.5 m) long. Pressure drop in the manifold is 3 psig

(20 kPa) and line leakage is 5%. Determine the pressure at the drill when all four drills are operating simultaneously and receiver pressure is 100 psig (690 kPa).