设A1,A2,A3,A4,A5的单价分别为x1,x2,x3,x4,x5元. 则依题意列得关系式如下:
| x1+3x2+4x3+5x4+6x5=1992① | x1+5x2+7x3+9x4+11x5=2984② |
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即 | (x1+x2+x3+x4+x5)+(2x2+3x3+4x4+5x5) =1992① | (x1+x2+x3+x4+x5)+2(2x2+3x3+4x4+5x5) =2984② |
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①×2-②式得: x1+x2+x3+x4+x5=2×1992-2984=1000. 所以购买每种教具各一件共需1000元. |