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: there is 60 lit of milk and water in which milk forms 84 % . howmuch water must be added to this solution to make it solution in which milk forms 64 % 
Options: a ) 18.75 , b ) 19.75 , c ) 20.75 , d ) 21.75 , e ) 22.75
[A]: a


[Q]: Problem: calculate how many seconds it will take for 4 bells to toll together again , given that they begin to toll together respectively at the intervals of 9 , 10 , 14 and 18 seconds . ? 
Options: a ) 636 , b ) 631 , c ) 633 , d ) 610 , e ) 630
[A]: e


[Q]: Problem: a candidate appearing for an examination has to secure 42 % marks to pass paper i . but he secured only 42 marks and failed by 22 marks . what is the maximum mark for paper i ? 
Options: a ) 110 , b ) 120 , c ) 130 , d ) 152 , e ) 150
[A]:
d