设去年甲球鞋卖了X双,乙球鞋卖了Y双。
则: X+Y=12200
(1+6%)X+(1-5%)Y=12200+50
1.06*X+0.95*Y=12250
Y=12200-X
1.06*X+0.95*(12200-X)=12250
0.11X=12250-11590=660
X=6000双
Y=12200-6000=6200双
去年甲球鞋卖了6000双,乙球鞋卖了6200双。
去年甲买了X双,乙12200-X双
(1+6%)X+(1-5%)(12200-X)=12200+50
0.11X=12200+50-0.95*12200=660
X=6000
12200-X=6200
去年:
甲+乙=12200
今年:
(1+0.06)甲+(1-0.05)乙=12200+50
1.06甲+0.95乙=12250
甲+(0.95/1.06)乙=12250/1.06
去年减今年的数式:
(1-1)甲+(1-0.95/1.06)乙=12200-12250/1.06
乘1.06:
(1.06-0.95)乙=1.06X12200-12250
乙=682/0.11=6200
甲=12200-6200=6000