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'.

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
b

Problem: a father said his son , ` ` i was as old as you are at present at the time of your birth . ` ` if the father age is 32 now , the son age 5 years back was 
Options: a ) 11 , b ) 17 , c ) 11 , d ) 19 , e ) 99
a

Problem: x + y = 19 , and x + 3 y = 1 . find the value of x + 2 y 
Options: a ) 20 , b ) 18 , c ) 11 , d ) 10 , e ) 5

d