A shopkeeper earns twice profit after selling an article in Rs.85 then the profit incurred after selling the article in Rs.65. Find cost price of the article.

45

Profit after selling the article at Rs.85 = 85 - C.P.

Profit after selling the article at Rs.65 = 65 - C.P.

ATQ,

85 - C.P. = 2 × (65 - C.P.)  

85 - C.P. = 130 - 2 C.P.

C.P. = 45