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'.

[Q]: Problem: a family made a down payment of $ 300 and borrowed the balance on a set of encyclopedias that cost $ 750 . the balance with interest was paid in 9 monthly payments of $ 57 each and a final payment of $ 21 . the amount of interest paid was what percent of the amount borrowed ? 
Options: a ) 6 % , b ) 12 % , c ) 14 % , d ) 18.66 % , e ) 20 %
[A]: d


[Q]: Problem: the banker ' s gain on a sum due 6 years hence at 12 % per annum is rs . 900 . what is the banker ' s discount ? 
Options: a ) 1240 , b ) 1120 , c ) 1190 , d ) 2150 , e ) none of these
[A]: d


[Q]: Problem: a $ 500 investment and a $ 1,500 investment have a combined yearly return of 19 percent of the total of the two investments . if the $ 500 investment has a yearly return of 7 percent , what percent yearly return does the $ 1,500 investment have ? 
Options: a ) 9 % , b ) 10 % , c ) 23 % , d ) 21 % , e ) 22 %
[A]:
c