Problem: a reduction of 20 % in the price of salt enables a lady to obtain 2 kgs more for rs . 100 , find the original price per kg ?
Rationale: "100 * ( 20 / 100 ) = 20 - - - 2 ? - - - 1 = > rs . 10 100 - - - 80 ? - - - 10 = > rs . 12.5 answer : c"
annotated_formula: multiply(divide(divide(multiply(divide(20, const_100), 100), 2), multiply(divide(20, const_100), 100)), const_100)