Set up a system of equations.
0.10d + 0.25q = 39.25
d + q = 250
Where 'd' represents the number of dimes, and 'q' represents the number of quarters.
d + q = 250
Subtract 'q' to both sides:
d = -q + 250
Plug in '-q + 250' for 'd' in the 1st equation:
0.10(-q + 250) + 0.25q = 39.25
Distribute 0.10:
-0.10q + 25 + 0.25q = 39.25
Combine like terms:
0.15q + 25 = 39.25
Subtract 25 to both sides:
0.15q = 14.25
Divide 0.15 to both sides:
q = 95
Now plug this into any of the two equations to find 'd':
d + q = 250
d + 95 = 250
Subtract 95 to both sides:
d = 155
So there are 95 quarters and 155 dimes.
