Problem: the price of an article is cut by 10 % . to restore it to the former value . the new price must be increased by ?
Rationale: answer let original price = rs . 100 . then , new price = rs . 90 . ∴ increased on rs . 90 = rs . 10 required increase % = ( 10 x 100 ) / 90 % = 111 / 9 % correct option : c
annotated_formula: add(subtract(const_100, subtract(const_100, 10)), const_2)