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: 90 students represent x percent of the boys at jones elementary school . if the boys at jones elementary make up 40 % of the total school population of x students , what is x ? 
Options: a ) 125 , b ) 150 , c ) 225 , d ) 250 , e ) 500
b

Problem: in country z , 10 % of the people do not have a university diploma but have the job of their choice , and 30 % of the people who do not have the job of their choice have a university diploma . if 40 % of the people have the job of their choice , what percent of the people have a university diploma ? 
Options: a ) 35 % , b ) 48 % , c ) 55 % , d ) 65 % , e ) 75 %
b

Problem: the value of a machine depreciates at 20 % per annum . if its present value is $ 1 , 50,000 , at what price should it be sold after two years such that a profit of $ 24,000 is made ? 
Options: a ) $ 250000 , b ) $ 430000 , c ) $ 120000 , d ) $ 170000 , e ) $ 150000

c