?? ????????50??????????????
????:1???????????:???????????
2????????
3?????vx
4????????98
5?????????
?1??????????????7????? (???? ??????????)?7??????????????????(?)???,??????????50??????????,?,???
??50???????????????????????,1????????7??9??5???(?????????????28.50???,??????????87.45?)????????6.8??,?????????????????????10????????10????4471?????????
?????????????????,???????????????(??)??????,?50?,??????????????????,?????????????,???(???????)
??????????????:?????????