Arithmetical method for solving practical problems Xiaofang has 50 stamps of 5 yuan, 2 yuan and 1 yuan, totaling 140 yuan. It is known that the number of stamps of 5 yuan and 2 yuan is the same. How many of these three stamps are there No equations

Let 5 yuan have X pieces, then 2 yuan have X pieces, 1 yuan have (50-x) pieces
5x+2x+(50-x）=140
7x+50-x=140
6x=90
x=15
A: there are 15 for 5 yuan, 15 for 2 yuan and 20 for 1 yuan

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