0.56÷(0.40-0.32)
=0.56÷0.08
=7(练习本比铅笔多的)
10-7×0.40
=10-2.8
=7.2(元) (把练习本比铅笔多的价钱减去了,铅笔和练习本的个数就一样了)
7.2÷(0.40+0.32)
=7.2÷0.72
=10(支) (铅笔的支数)
10+7=17(本) (练习本的本数)
设老师原想让小虎买x本练习本,y支铅笔
0.4x+0.32y=10
0.4y+0.32x=10-0.56
联立方程组,算出x,y即可
+0.32)
=10(支) (铅笔的支数) 1
10+7=17(本) (练习本的本数) 111
0.4x+0.32y=10
0.4y+0.32x=10-0.56