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: total dinning bill for 6 people was $ 211.00 . if they add 15 % tip and divided the bill evenly , approximate . what was each persons find share 
Options: a ) $ 30.14 , b ) 40.44 , c ) 34.66 , d ) 32.29 , e ) 33.16
[EX A]: b

[EX Q]: Problem: if a - b = 5 and a 2 + b 2 = 31 , find the value of ab . 
Options: a ) 9 , b ) 2 , c ) 3 , d ) 7 , e ) 12
[EX A]: c

[EX Q]: Problem: the ratio 25 : 50 expressed as percent equals to 
Options: a ) 50 % , b ) 85 % , c ) 25 % , d ) 75 % , e ) none of above
[EX A]:
a