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: a , b and c started a business with a total investment of rs . 90000 . a invests rs . 6000 more than b and b invests rs . 3000 less than c . if the total profit at the end of a year is rs . 8640 , find b ' s share . 
Options: a ) rs . 2592 , b ) rs . 2520 , c ) rs . 2880 , d ) rs . 3360 , e ) none of these
[EX A]: a

[EX Q]: Problem: set s contains exactly 10 numbers and has an average ( arithmetic mean ) of 6.2 . if one of the numbers in set s is increased by 8 , while all other numbers remain the same , what is the new average of set s ? 
Options: a ) 6.6 , b ) 6.7 , c ) 6.8 , d ) 7.0 , e ) 6.9
[EX A]: d

[EX Q]: Problem: the average age of 30 students in a class is 15 years . if the age of teacher is also included , the average becomes 16 years , find the age of the teacher . 
Options: a ) 46 , b ) 55 , c ) 43 , d ) 39 , e ) 54
[EX A]:
a