Xavior took a total of 124 quarters and dimes to trade in for cash at the bank. He got exactly $25 back. How many quarters did he have
Let's assume Xavior had q quarters. Since he also had a total of 124 coins, he must have had a total of 124 - q dimes.
The value of q quarters is 0.25q dollars.
The value of (124 - q) dimes is 0.10(124 - q) dollars.
The total value of the coins is 0.25q + 0.10(124 - q) = 25 cents.
0.25q + 12.4 - 0.10q = 25
0.15q + 12.4 = 25
0.15q = 12.6
q = 12.6 / 0.15
q = <<84=84>>84 quarters. Answer: \boxed{84}.