Two brothers took the GMAT exam, the higher score is X and the lower one is Y. If the difference between the two scores is 1/3, what is the value of X/Y ? Choose the correct answer:  A) 3 .  B) 2 .  C) 1 / 2 .  D) 4  E) there is n ' t enough data to answer the question .

Rationale: answer is d : 4 x - y = ( x + y ) / 2 solving for x / y = 4
Answer: D