If x+y=3 and x2y3 + y2x3=27, what is the value of xy? Choose one:
A) 1
B) 2
C) 3
D) 4
E) 5

Rationale: "xy = 3 as x + y = 3 x 2 y 3 + y 2 x 3 = 27 x 2 y 2 ( y + x ) = 27 substituting x + y x 2 y 2 = 9 xy = 3 answer : c"
Answer: C