The price of an article is cut by 10%. To restore it to

The price of an article is cut by 10%. To restore it to the former value. The new price must be increased by ?

Let original price = Rs. 100.
Then, new price = Rs. 90.
∴ Increased on Rs. 90 = Rs. 10
Required increase % = (10 x 100) / 90 % = 11¹/₉%