TASK DEFINITION: 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: Problem: a retailer bought a machine at a wholesale price of $ 90 and later on sold it after a 10 % discount of the retail price . if the retailer made a profit equivalent to 20 % of the whole price , what is the retail price t of the machine ? 
Options: a ) 81 , b ) 100 , c ) 120 , d ) 135 , e ) 160

SOLUTION: c

PROBLEM: Problem: by selling an article for $ 110 , a person gains $ 10 . what is the gain % ? 
Options: a ) 25 % , b ) 30 % , c ) 50 % , d ) 20 % , e ) 10 %

SOLUTION: e

PROBLEM: Problem: there are two groups of students in the sixth grade . there are 30 students in group a , and 50 students in group b . if , on a particular day , 20 % of the students in group a forget their homework , and 12 % of the students in group b forget their homework , then what percentage of the sixth graders forgot their homework ? 
Options: a ) 13 % , b ) 14 % , c ) 15 % , d ) 16 % , e ) 17 %

SOLUTION:
c