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: at the end of the month , a certain ocean desalination plant ’ s reservoir contained 26 million gallons of water . this amount is eighth the normal level . if this amount represents 65 % of the reservoir ’ s total capacity , how many million gallons short of total capacity is the normal level ? 
Options: a ) 15 , b ) 25 , c ) 35 , d ) 45 , e ) 55
[A]: c


[Q]: Problem: in an acoustics class , 120 students are male and 100 students are female . 25 % of the male students and 20 % of the female students are engineering students . 20 % of the male engineering students and 25 % of the female engineering students passed the final exam . what percentage of engineering students passed the exam ? 
Options: a ) 5 % , b ) 10 % , c ) 16 % , d ) 22 % , e ) none of these
[A]: d


[Q]: Problem: joe invested a certain sum of money in a simple interest bond whose value grew to $ 260 at the end of 3 years and to $ 360 at the end of another 5 years . what was the rate of interest in which he invested his sum ? 
Options: a ) 6 % , b ) 8 % , c ) 10 % , d ) 12 % , e ) 15 %
[A]:
c