???,?
?????????????????????????
? :?????? ,? ,?? 1 ,????? 2
?????????????????????????????
?
1.???
????????15????10??5? ?3??6?
????315???20??????????
??
2.??1???????5??????10?750??????????????????????????20-30?????????????????????
????????
1??
??? ????????
2?
????????????
3??
????????????????
4???
????????????????????????20???????????????
5??
?????5?10?
6??
???50100????
7?
}???}?1?2???????????12????????????12??