



 
Hi Edward, Suppose the storekeeper has some good that cost him $\$C.$ If he marks up his goods to gain $35\%$ then he adds $35\%$ of $\$C$ to $\$C$ to obtain the selling price. This the selling price $\$S$ is given by \[\$S = \$C + 0.35 \times $C = 1.35 \times \$C.\] If you pay cash then you get a $10\%$ discount so to you the selling price is $\$S  0.10 \times \$S = 0.90 \times \$S.$ In this case what is his profit as a percentage of $\$C?$ Penny  


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