Question 989611
n = number of nickels
d = number of dimes
q = number of quarters


n + d + q = 42
n = d + 8
5n + 10d + 25q = 715


Substitute the second equation into the first and third equations.


2d + q = 34
15d + 25q = 675


Multiply the first equation by 25.


50d + 25q = 850
-(15d + 25q = 675)
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35d = 175
d = 5


Gary has 5 dimes, 24 quarters, and 13 nickels.