单项选择题
A.50/450×100/100=11.11% B.200/450×100/100=44.44% C.450/500×100/100=90% D.400/550×100/100=81.82% E.450/650×100/100=53.85%
A、300/450×100/1000=66.67% B、200/450×100/100=44.44% C、450/500×100/100=90% D、200/500×100/100=40% E、300/500×100/100=60%
A.2.0 B.8.0 C.10.0 D.1.6 E.0.4