If xy=4, x/y=81, for positive numbers x and y, y=?
Choose the correct choice from the following choices:	A) 1 / 2	B) 2	C) 2 / 9	D) 3	E) 1 / 6

Rationale: "very easy question . 2 variables and 2 easy equations . xy = 4 - - - > x = 4 / y - ( i ) x / y = 81 - - - > replacing ( i ) here - - - > 4 / ( y ^ 2 ) = 81 - - - > y ^ 2 = 4 / 81 - - - > y = 2 / 9 or - 2 / 9 the question states that x and y are positive integers . therefore , y = 2 / 9 is the answer . answer c ."
Answer: C