Marsha has nickels, dimes, and quarters. She has 207 coins total. Marcy has 13 less quarters than nickels. Find the number of each coin if she has a total of $28.

Answer 1

nickels --- x
quarters ---- x-13
dimes --- 207 - (x + x-13) = 220 - 2x

solve for x:

5x + 25(x-13) + 10(220-2x) = 2800
5x + 25x - 325 + 2200 - 20x = 2800
10x = 925

but x should be a whole number,
Unless I made a silly arithmetic error, your data is not consistent.