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: john found that the average of 15 numbers is 40 . if 12 is added to each number then the mean of number is ?
Options: a ) 52 , b ) 45 , c ) 65 , d ) 78 , e ) 64
a

Problem: how much percentage 80 is of 480 ?
Options: a ) 16.5 , b ) 14.33 , c ) 12.5 , d ) 15.8 , e ) 16.66
e

Problem: john was thrice as old as tom 6 years ago . john will be 7 / 5 times as old as tom in 6 years . how old is tom today ?
Options: a ) 7 , b ) 9 , c ) 11 , d ) 13 , e ) 15
b