There are 54 coins Let x be the number of quarters.....then 54-x is the number of nickles
.25 x = value of quarters
.05 (54-x) = value of nickles..... added together, these must equal 9.10
.25x + .05(54-x) = 9.10 solve for 'x',,,the number of quarters, the rest will be nickles (54-x)
Go !