A grocery customer spent a total of $9.6 for ground beef and coffee.The coffee cost 2 times as much per pound as the gro
问题描述：
A grocery customer spent a total of $9.6 for ground beef and coffee.The coffee cost 2 times as much per pound as the ground beef,and the customer bought 3 times as many pounds of ground beef.How much,in dollars,did the customer spend on coffee
答
设卖牛肉次数为y,价格为a,买咖啡次数为z,价格为c,据题意,得
2a=c （1）
y=3z （2）
ay+cz=9.6 （3）
他球的是咖啡总价,即cz=,
所以要用有cz的式子表示,变形（1)得a=c/2,
吧（1）（2）代入得1.5cz+cz=9.6
2.5cz=9.6
cz=3.84