A shopkeeper earns a profit of 10% after allowing a discount

A shopkeeper earns a profit of 10% after allowing a discount of 20% on the marked price. The cost price of the article whose marked price is ₹ 880, is

Given Here , marked price = ₹ 880
SP of article = (100 – 20)% of 880 = 80% of 880
Let CP be y
Again, 110% of y = 704

y =	704	× 100 = ₹ 640
	110

∴ Original cost = ₹ 640
We can find required answer with the help of given formula :
Here, r = 10%, D = 20%, M.P. = ₹ 880, C.P. = ?

M.P.	=	100 + r
C.P.	=	100 − D

880	=	100 + 10
C.P.	=	100 − 20

880	=	110
C.P.	=	80

C.P. =	880 × 80
	110

C.P. = ₹ 640