If 4/p=8 & 4/q=18 then p-q=?  Choose the correct choice from the following answers.
A) 5 / 18  B) 6 / 24  C) 7 / 24  D) 8 / 24  E) 9 / 24

Rationale: "p = 4 / 8 , q = 4 / 18 = > q = 2 / 9 therefore p - q = ( 1 / 2 ) - ( 2 / 9 ) = 5 / 18 answer : a"
Answer: A