Question

A shopkeeper sells an article at 15%gian . had he sold it for r18 mote , he would gain 18% find the cost of article

Answer 1

let cp be x
sp=115x/100
if he had sold it for 18 more then sp=115x /100+ 18
gain 18% means sp=118x/100
115x /100+18=118x/100
3x/100=18
x=600

Answer 2

Let the cost price be x

so the gain is 15x/100

selling price = cost price +gain

=x+15x/100

=115x/100

If he sells for Rs 18 more than he will gain 18%

If he gain 18% the selling price will be 118x/100

so

115x/100+18=118x/100

118x/100-115x/100=18

3x=1800

x=600

so the cost price of article is Rs 600