Q, D, P = numbers of quarters, dimes and pennies. Q+D+P=20. P=5D, so Q+D+5D=20 and Q+6D=20.
Value=25Q+10D+P=230 pennies, so 25Q+10D+5D=230, 25Q+15D=230, so 25Q=230-15D, 5Q=46-3D.
Q=20-6D, so 5Q=100-30D=46-3D. 54=27D, D=2, P=5*2=10 and Q=20-6*2=8.
CHECK: Q+D+P=8+2+10=20. VALUE=8*0.25+2*0.10+0.10=$2.30.
Solution: 8 quarters, 2 dimes, 10 pennies.