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: the average of first seven prime numbers which are between 30 and 70 is 
Options: a ) 35.4 , b ) 42 , c ) 44.4 , d ) 57 , e ) 67
c

Problem: if ( x + 3 ) ^ 2 / ( 2 x + 15 ) = 3 , then the difference between the two possible values of x is : 
Options: a ) 8 , b ) 10 , c ) 12 , d ) 14 , e ) 16
c

Problem: the average of 6 quantities is 8 . the average of 4 of them is 5 . what is the avg . of the remaining 2 numbers ? 
Options: a ) 11 , b ) 12 , c ) 13 , d ) 14 , e ) 15

d