Question

how much percent above the cost price should a shopkeeper mark his goods so that after allowing a discount of 20% on the Marked price he gains is 12%

Answer 1

let the CP be Rs. 100 and MP be Rs. x
gain % after discount = 12%
gain = 12% of 100 = Rs. 12
⇒ SP of the article = CP + Gain
= Rs. (100 + 12) = Rs. 112
Discount % = 20%
Discount = 20% of Marked Price
 = Rs.20/100 * x
= Rs. 20x/100
= Rs. x/5
as da question says
marked Price - discount = SP
=> x - x/5 = 112
=> (5x - x)/5 = 112
=> 4x/5 = 112
=> x = 112 * 5/4 = Rs. 140
marked Price = Rs. 140
amount marked above the CP = MP - CP
= Rs. (140 - 100)
= Rs. 40
∴ % amount marked above the CP
= Amount increased/CP * 100
= 40/100 * 100
= 40%