Question 158960
N+D=30 OR N=30-D
.05N+.10D=2.10
.05(30-D)+.10D=2.10
1.50-.05D+.10D=2.10
.05D=2.10-1.50
.05D=.60
D=.60/.05
D=12 DIMES.
N+12=30
N=30-12
N=18 NICKLES.
PROOF
.05*18+.10*12=2.10
.90+1.20=2.10
2.10=2.10