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 house wife saved $ 2.50 in buying an item on sale . if she spent $ 25 for the item , approximately how much percent she saved in the transaction ? 
Options: a ) 8 % , b ) 9 % , c ) 10 % , d ) 11 % , e ) 12 %
[EX A]: b

[EX Q]: Problem: if x / 4 years ago roger was 14 years old and x / 4 years from now he will be 4 x years old , how old will he be 6 x years from now ? 
Options: a ) 32 , b ) 39 , c ) 30 , d ) 40 , e ) 28
[EX A]: b

[EX Q]: Problem: if a - b = 9 and a ^ 2 + b ^ 2 = 281 , find the value of ab 
Options: a ) 100 , b ) 12 , c ) 15 , d ) 18 , e ) 19
[EX A]:
a