一盒饼干连盒重500克,吃了5分之3,连盒重230克.原有饼干与盒子各重多少克?

设原有饼干xg,盒子重yg
x+y=500(1)
2/5x+y=230(2)
(1)-(2) 3/5x=270
x=450
y=500-x=500-450=50
答:原有饼干450g,盒子重50g