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: find the compound interest on $ 50000 in 2 years at 4 % per annum , the interest being compounded half - yearly ? 
Options: a ) $ 645.56 , b ) $ 4121.60 , c ) $ 954.26 , d ) $ 745.69 , e ) $ 1020.45
[EX A]: b

[EX Q]: Problem: the simple interest on rs . 20 for 6 months at the rate of 5 paise per rupeeper month is 
Options: a ) 1.2 , b ) 1.4 , c ) 6 , d ) 7 , e ) none
[EX A]: c

[EX Q]: Problem: the cost price of 30 articles is the same as the selling price of x articles . if the profit is 25 % , what is x ? 
Options: a ) 18 , b ) 20 , c ) 22 , d ) 24 , e ) 26
[EX A]:
d