Respuesta :

AL2006
8 quarters = $2.00
5 nickles = $0.25

Total ... 13 coins = $2.25
n-nickels, q-quarters

n+q=13=>n=13-q

0.25q+0.05n=2.25
0.25q+0.05(13-q)=2.25
0.25q+0.65-0.05q=2.25
0.20q=2.25-0.65
0.20q=1.6
q=1.6:0.2
q=8
n=13-8
n=5