In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: how much 60 % of 50 is greater than 30 % of 30 ? 
Options: a ) 21 , b ) 91 , c ) 11 , d ) 17 , e ) 12
a

Problem: in an acoustics class , 120 students are male and 100 students are female . 25 % of the male students and 20 % of the female students are engineering students . 20 % of the male engineering students and 25 % of the female engineering students passed the final exam . what percentage of engineering students passed the exam ? 
Options: a ) 5 % , b ) 10 % , c ) 16 % , d ) 22 % , e ) none of these
d

Problem: a reduction of 30 % in the price of salt enables a lady to obtain 10 kgs more for rs . 100 , find the original price per kg ? 
Options: a ) 2.8 , b ) 2.3 , c ) 2.5 , d ) 2.1 , e ) 4.3

e