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: the price of a book is increased from $ 300 to $ 480 . what is the % of increase in its price ? 
Options: a ) 10 % , b ) 20 % , c ) 40 % , d ) 50 % , e ) 60 %

SOLUTION: e

PROBLEM: Problem: a number increased by 20 % gives 480 . the number is ? 
Options: a ) 200 , b ) 300 , c ) 400 , d ) 500 , e ) 600

SOLUTION: c

PROBLEM: Problem: john and david can finish a job together in 3 hours . if john can do the job by himself in 4 hours , what percent of the job does david do ? 
Options: a ) 35 % , b ) 28 % , c ) 26 % , d ) 20 % , e ) 25 %

SOLUTION:
e