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: in country x a returning tourist may import goods with a total value of $ 500 or less tax free , but must pay an 8 percent tax on the portion of the total value in excess of $ 500 . what tax must be paid by a returning tourist who imports goods with a total value of $ 730 ? 
Options: a ) $ 58.40 , b ) $ 40 . 00 , c ) $ 24.60 , d ) $ 18.40 , e ) $ 16.00
[EX A]: d

[EX Q]: Problem: if x ^ 2 + y ^ 2 = 15 and xy = 3 , then ( x − y ) ^ 2 = 
Options: a ) 8 , b ) 9 , c ) 14 , d ) 17 , e ) 20
[EX A]: b

[EX Q]: Problem: a two - digit number is such that the product of the digits is 8 . when 18 is added to the number , then the digits are reversed . the number is ? 
Options: a ) 1 , b ) 2 , c ) 6 , d ) 8 , e ) 9
[EX A]:
b