Need !

every evening jenna empties her pockets
and puts her change in a jar. at the end
of the week she counts her money. one
week she had 50 coins, all of them dimes
and quarters. when she added them up,
she had a total of $10.25.

let d = number of dimes and
q = number of quarters.

D + q = 50

10d + 25q = 1025

Multiply the first equation by 10. 

10(d + q = 50) --> 10d + 10q = 500

We combine this with the second equation

10d + 25q = 1025 
10d + 10q = 500

subtract
15q = 525 iff
q = 35

Plug in q = 35 into any of the original equations,

d + q = 50
d + 35 = 50 iff
d = 15

There are 15 dimes, and 35 quarters.

The answer is