Answer: D=40, Q=60
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!