Question

Stella has 63 coins. The coins are a mixture of quarters and dimes. She has a total of $10.80. How many quarters and how many dimes does Stella have

Answer 1

Q + d = 63....q = 63 - d
0.25q + 0.10d = 10.80

0.25(63 - d) + 0.10d = 10.80
15.75 - 0.25d + 0.10d = 10.80
-0.25d + 0.10d = 10.80 - 15.75
-0.15d = -4.95
d = -4.95/-0.15
d = 33 <=== 33 dimes

q + d = 63
q + 33 = 63
q = 63 - 33
q = 30 <=== 30 quarters

Answer 2

So if Stella has 63 coins, then the number of quarters and dimes that she has will equal up to 63.
___ quarters
___ dimes
63 coins in total
$10.80 in total.
I used the guess and check method, which means that I estimated around the number of quarters an dimes, and it took me a few tries but here is what I got, and I checked it as well. You can check it to if you want.

Stella has 30 quarters and 33 dimes to make $10.80 in change.
30 * 0.25 = 7.50
33 * 0.10 = 3.30
7.50 + 3.30 = 10.80

So therefor it is correct 3o of the 3 coins Stella has are quarters, and 33 of them are dimes. Hope this helps and have a wonderful day.