Let d = # of dimes Let q = # of quarters 45 = d + q .1d + .25q = 8.40 Then we can use the substitution method and make it so that d = 45 - q. Then plug in the value for d into the second equation. .1(45-q)+.25(q)=8.40 4.5-.1q+.25q=8.40 4.5+.15q = 8.40 .15q = 3.90 q = 26 d = 45 - 26 = 19 26 quarters 19 dimes