Ashley had an equal number of dimes and quarters until she gave 15 quarters away. She now has $ 22.50 in dimes and quarters. How many dimes does she have?

1 answer

at start,
number of dimes --- x
number of quarters -- x

after give-away:
dimes = x
quarters = x-15

10x + 25(x-15) = 2250

solve for x