Question

Lisa has twelve fewer dimes than quarters, for a total of $11.05

Answer 1

So set up the equations
q-12=d
25q+10d=1105
plug in q-12 as d in the second equation:
25q+10q-120=1105, then simplify:
35q=1225
q=35
since there's 12 fewer dimes, we know that there's 23 dimes and 35 quarters.