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: evaluate 64 / . 08 
Options: a ) 800 , b ) 500 , c ) 505 , d ) none of these , e ) 506

A: a
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Q: Problem: if two of the 4 expressions x + y , x + 5 y , x - y , and 5 x - y are chosen at random , what is the probability w that their product will be of the form of x ^ 2 - ( by ) ^ 2 , where b is an integer ? 
Options: a ) 1 / 2 , b ) 1 / 3 , c ) 1 / 4 , d ) 1 / 5 , e ) w = 1 / 6

A: e
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Q: Problem: when x is multiplied by 3 , the result is 20 more than the result of subtracting x from 20 . what is the value of x ? 
Options: a ) 10 , b ) - 2 , c ) 11 , d ) 13 , e ) 22

A:
a
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