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: 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

Problem: a sum of money at simple interest amounts to rs . 825 in 3 years and to rs . 846 in 4 years . the sum is ? 
Options: a ) s . 738 , b ) s . 638 , c ) s . 650 , d ) s . 762 , e ) s . 735
d

Problem: 33 1 / 3 % of 390 ? 
Options: a ) 80 , b ) 90 , c ) 110 , d ) 120 , e ) 130

e