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'.

[EX Q]: Problem: the average marks of a class of 40 students is 44 and that of another class of 45 students is 70 . find the average marks of all the students ?
Options: a ) 52.6 , b ) 52.4 , c ) 52.1 , d ) 69.5 , e ) 52.9
[EX A]: d

[EX Q]: Problem: a ' s speed is 20 / 15 times that of b . if a and b run a race , what part of the length of the race should a give b as a head start , so that the race ends in a dead heat ?
Options: a ) 1 / 17 , b ) 3 / 17 , c ) 1 / 10 , d ) 5 / 20 , e ) 3 / 10
[EX A]: d

[EX Q]: Problem: the difference between the value of a number increased by 25 % and the value of the original number decreased by 30 % is 22 . what is the original number ?
Options: a ) 40 , b ) 50 , c ) 65 , d ) 70 , e ) 90
[EX A]:
a