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 marks of a class of 30 students is 40 and that of another class of 50 students is 60 . find the average marks of all the students ? 
Options: a ) 82.5 , b ) 52.9 , c ) 52.2 , d ) 52.5 , e ) 52.7
[A]: d


[Q]: Problem: a number is doubled and 5 is added . if the resultant is trebled , it becomes 123 . what is that number ? 
Options: a ) 12 , b ) 29 , c ) 27 , d ) 18 , e ) 99
[A]: d


[Q]: Problem: alok ordered 16 chapatis , 5 plates of rice , 7 plates of mixed vegetable and 6 ice - cream cups . the cost of each chapati is rs . 6 , that of each plate of rice is rs . 45 and that of mixed vegetable is rs . 70 . the amount that alok paid the cashier was rs . 1051 . find the cost of each ice - cream cup ? 
Options: a ) 25 , b ) 40 , c ) 77 , d ) 99 , e ) 91
[A]:
b