If 2/w + 2/x = 2/y and wx = y, then the average (arithmetic mean) of w and x is
Options
A) 1 / 2  B) 1  C) 2  D) 4  E) 8

Rationale: "given : 2 / w + 2 / x = 2 / ywx = y find : ( w + x ) / 2 = ? 2 ( 1 / w + 1 / x ) = 2 ( 1 / y ) - divide both sides by 2 ( 1 / w + 1 / x ) = 1 / y ( x + w ) / wx = 1 / wx - sub ' d in y = wx x + w - 1 = 0 x + w = 1 therefore ( w + x ) / 2 = 1 / 2 ans : a"
Answer: A