# A shopkeeper sells an article at Rs. 40 and gets X% profit

A shopkeeper sells an article at Rs. 40 and gets X% profit. However, when he sells it at Rs. 20, he faces same percentage of loss. What is the original cost of the article?

1. Rs. 10
2. Rs. 20
3. Rs. 30
4. Rs. 40

Profit and loss is calculated on the cost price. Let the cost price of the article be P.

Profit % = Loss %

(40 - P)/P = (P - 20)/P

2P = 60

P = 30

The correct option is C.