a bag contains 57 coins which are only quarters and dimes the total value of coins is $9.45 how many dimes are in the bag

There are 32 dimes and 25 quarters.

Step-by-step explanation:

q + d = 57 or q = 57 - d

25q + 10d = 945

substitute first equation into second equation:

25 (57 - d) + 10d = 945

1425 - 25d + 10d = 945

-15d = - 480

d = - 480/-15 = 32

using first equation:

q = 57 - 32 = 25

check using second equation:

25 (25) + 10 (32) = 945 checks