Respuesta :

d + q = 25.....d = 25 - q
0.10d + 0.25q = 3.55

0.10(25 - q) + 0.25q = 3.55
2.50 - 0.10q + 0.25q = 3.55
-0.10q + 0.25q = 3.55 - 2.50
0.15q = 1.05
q = 1.05 / 0.15
q = 7 <=== there are 7 quarters

d + q = 25
d + 7 = 25
d = 25 - 7
d = 18.....and 18 dimes