Kitara has 100 quarters and dimes. Their total value is $19. How many of each coin does she have?

D=40, Q=60

Step-by-step explanation:

First make two equations

Q+D=100 Kitara has 100 quarters and dimes

0.25Q+0.1D=19 Their total value is $19

then solve for one

0.25(100-D)+0.1D=19

25-0.25D+0.1D = 19

25-.15D=19

6=0.15D

D=40

Then solve for the other

D+Q=100, D=40 therefore Q=60

Double check  

40*.1+60*.25=19

4+15=19 check!