9.to make a food, one may use chocolate and peanut, the cost of 2 pounds chocolate and 3 pounds peanut to make such a food is 3.8 per pound, if the cost of chocolate is 2 more than (or less than) that of peanut, how much does peanut cost? 设the cost of chocolate is x ,那么the cost of peanut就是x-2或者x+2 所以2x+3(x-2)=3.8*5 求出x=5 那么the cost of peanut 就为3 小妞同学我不明白呀,那个3.8*5 是怎么出来的呀?  -- by 会员 zhangyingpin (2010/5/26 11:57:50)
因为有2 pounds chocolate and 3 pounds peanut 所以总共有5pounds |