1st: 3b+5s=2.31 2nd: 5b+3s=3.05Multiply 1st by 5 to get:3rd: 15b+25s=11.55Multiply 2nd by 3 to get:4th: 15b+9s=9.15Subtract 4th from 3rd to get: 16s=2.4 s=0.15 or 15 cents (cost of bar of soap)Substitute into 1st to solve for b:3b+5(0.15)=2.313b+0.75=2.313b=1.56b=0.52 or 52 cents (cost of a sponge)