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: if the cost price of 55 articles is equal to the selling price of 50 articles , then what is the percent profit ? 
Options: a ) 5 % , b ) 10 % , c ) 15 % , d ) 20 % , e ) 25 %
b

Problem: what percent of 120 are 90 ? 
Options: a ) 25 % , b ) 50 % , c ) 75 % , d ) 33 % , e ) 30 %
c

Problem: a man sold 20 articles for $ 60 and gained 20 % . how many articles should he sell for $ 90 to incur a loss 10 % ? 
Options: a ) 45 , b ) 41.2 , c ) 40 , d ) 50 , e ) 48

b