Let x = the number of quarters
Then 60 - x = the number of dimes
.25x + .1(60-x) = 9.45 - number of quarters times their money value plus the number of dimes times their money value equals the total amount of money.
Solve for x
.25x + 6 - .1x = 9.45
.15x = 3.45
x = 23 - number of quarters
60 - x = number of dimes
60 - 23
37 - dimes