???????2,????????,???????2????????淨(jìng)
?3?????????????????????С????????????????? ?????????鯔???????????£?
150??5???????20???????300?????????300?????150??+20????
????????30000?????15000??+2000????50000?????25000??+3300????
4???????=1??30??????Ρ?
????β??????????????????30~40???
?????????????Σ?5??400???
5??=150??--->400??
400?????????????100?????????????????????????
?????????????????150??????100??????????????40~50????
????????>1000?????????????100?ú???200??1??????+20????????
???????2??????????? ????1-13???????????