Question 971689
x+y=100
x=100-y
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0.07x+0.09y=8.40
0.07(100-y)+0.09y=8.40
7-0.07y+0.09y=8.40
0.02y=8.40-7
y=1.40/0.02
y=70
x=100-70
x=30