By selling an item for Rs. 24, the shopkeeper earns the percentage profit equal to cost price of the item. Find the cost price.
20
Let the cost price be x
Profit on the item is 24−x
Profit % = S.P−C.PC.P×100
=24−xx×100
Given that the profit percentage is equal to the cost price.
⇒24−xx×100=x
⇒x2=2400−100x
⇒x2−2400+100x=0
⇒x2+120x−20x−2400=0
⇒(x+120)(x−20)=0
⇒x=−120 or 20
Cost price of an item cannot be negative.
So, the cost price is Rs. 20