Question 172826
Let D=the number of dimes.
Let N=the number of nickles.
.10D+.05N=7.05 (multiply this equation by -2 & add to the other equation
.10*2D+.05(N+8)=11.75
.20D+.05N+.40=11.75
.20D+.05N=11.75-.40
.20D+.05N=11.35
-.20D-.10N=-14.10
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-.05N=-2.75
N=-2.75/-.05
N=55 nickles.
.10D+.05*55=7.05
.10D+2.75=7.05
.10D=7.05-2.75
.10D=4.30
D=4.30/.10
D=43 dimes.
Proof:
.20*43+.05*55=11.35
8.60+2.75=11.35
11.35=11.35