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'.

[EX Q]: Problem: if the simple interest on a certain sum of money for 5 years is one – fifth of the sum , then the rate of interest per annum is 
Options: a ) 4 % , b ) 7 % , c ) 6 % , d ) 4 % , e ) 3 %
[EX A]: d

[EX Q]: Problem: a computer store offers employees a 10 % discount off the retail price . if the store purchased a computer from the manufacturer for $ 1200 dollars and marked up the price 10 % to the final retail price , how much would an employee save if he purchased the computer at the employee discount ( 10 % off retail price ) as opposed to the final retail price . 
Options: a ) 122 , b ) 132 , c ) 142 , d ) 152 , e ) 162
[EX A]: b

[EX Q]: Problem: if 40 % of a certain number is 160 , then what is 30 % of that number ? 
Options: a ) 270 , b ) 380 , c ) 120 , d ) 360 , e ) 180
[EX A]:
c