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'.

[Q]: Problem: in an office , 20 percent of the workers have at least 5 years of service , and a total of 16 workers have at least 10 years of service . if 90 percent of the workers have fewer than 10 years of service , how many of the workers have at least 5 but fewer than 10 years of service ? 
Options: a ) 32 , b ) 64 , c ) 50 , d ) 144 , e ) 160
[A]: a


[Q]: Problem: the population of a town is 30000 . it decreases annually at the rate of 20 % p . a . what will be its population after 2 years ? 
Options: a ) 4300 , b ) 19200 , c ) 5120 , d ) 5230 , e ) 5366
[A]: b


[Q]: Problem: compound interest of rs . 4000 at 10 % per annum for 1 1 / 2 years will be ( interest compounded half yearly ) . 
Options: a ) rs . 473 , b ) rs . 374 , c ) rs . 495 , d ) rs . 630 , e ) none of the above
[A]:
d