In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[Q]: Problem: the average of the marks of 30 students in a class is 45 . if the marks of each student are doubled , find the new average ?
Options: a ) 85 , b ) 77 , c ) 33 , d ) 90 , e ) 75
[A]: d

[Q]: Problem: it takes 30 days to fill a laboratory dish with bacteria . if the size of the bacteria doubles each day , how long did it take for the bacteria to fill one sixteenth of the dish ?
Options: a ) 16 days , b ) 26 days , c ) 27 days , d ) 28 days , e ) 29 days
[A]: b

[Q]: Problem: a 40 - liter solution of alcohol and water is 5 percent alcohol . if 6.5 liters of alcohol and 3.5 liters of water are added to this solution , what percent of the solution produced is alcohol ?
Options: a ) 13 % , b ) 14 % , c ) 15 % , d ) 16 % , e ) 17 %
[A]:
e