We can use a systems of equations for this. We know that there are quarters ($0.25), and there are dimes ($0.10). We can make our first equation:
0.25q + 0.10d = 12.70
Next, we know that there are 73 coins in total.
q + d = 73
Once we solve this, we get d = 37 and q = 36. She has 37 dimes, and she has 36 quarters.
