Joey has 5.75 made up of all dimes and quarters. If joey has 38 coins. How many of each each coin does he have?

D + q = 38 ... d = 38 - q

0.10d + 0.25q = 5.75

0.10 (38 - q) + 0.25q = 5.75

3.80 - 0.10q + 0.25q = 5.75

-0.10q + 0.25q = 5.75 - 3.80

0.15q = 1.95

q = 1.95/0.15

q = 13 < = = = 13 quarters

d + q = 38

d + 13 = 38

d = 38 - 13

d = 25 < = = = 25 dimes

Quarters = 13 dimes = 25 is the correct answer