Question 271339
N+D=30
N=30-D
.05N+.10D=2.10
.05(30-D)+.10D=2.10
1.5-.05D+.10D=2.10
.05D=2.10-1.50
.05D=.60
D=.60/.05
D=12 NUMBER OF DIMES.
N=30-12
N=18 NUMBER OF NICKELS.
PROOF:
.05*18+.10*12=2.10
.90+1.20=2.10
2.10=2.10