A.7.57B.9.15C.10.15D.11.15
A.經(jīng)濟效果大于0 B.經(jīng)濟效果小于0 C.經(jīng)濟效果不小于0 D.勞動耗費小于0
A.40 B.50 C.51.38 D.52.76