Question 183824
N+D=20 OR N=20-D
.05N+.10D=1.75
.05(20-D)+.10D=1.75
1-.05D+.10D=1.75
.05D=1.75-1
.05D=.75
D=.75/.05
D=15 IS THE NUMBER OF DIMES.
20-15=5 IS THE NUMBER OF NICKELS.
PROOF
.05*5+.10*15=1.75
.25+1.50=1.75
1.75=1.75