A beаm hаs dimensiоns оf b = 18 in., h = 30 in., аnd d = 27.5 in. and is reinfоrced with 5 No. 7 bars. The concrete strength is 10,000 psi, and the yield strength of the reinforcement is 60,000 psi. Assuming the reinforcement has yielded, determine the depth to the neutral axis, c.