The marked price of an article is 30% higher than the cost price. If a trader sells the articles allowing 10% discount to customer, then the gain percent will be

solution

let cost price (CP) = rs 100

MP (marked price) = 30% more than cost price = $$\frac{30}{100} \times$$100 = 30 + 100 { here 100 =CP}

MP =rs 130

discount% = 10%                     

discount = 10% of 130 = rs 13    { $$\because $$ discount = $$ \frac{discount percent}{100} \times $$ MP}

So selling price SP = 130 -13 = 117 {  $$\because $$SP = MP- discount}

gain = 117 - 100 = 17 {$$\because $$ gain = SP-CP}

gain % = $$\frac{17}{100} \times$$100 = 17%