If x and y are positive, which of the following must be greater than 1 / sqt root of (x + y)

I) sqt root of (x+y) / 2x

II) sqt root of (x) + sqt root of (y) / x + y

III) sqt root of (x) - sqt root of (y) / x + y

A) none B) I C) II only D) I and III E) II amd III

MULTIPLY STEM BY SQRT(X+Y) / SQRT(X+Y) IT WILL LOOK BETTER

IE: SQRT(X+Y) /( X+Y)

FROM ONE COMPARING (X+Y) TO 2X DEPENDS.......OUT (B,D OUT)

NOW WE COMPARE SQRT X + SQRT Y TO SQRT( X+Y) ....

ASSUME X = 9 ,Y = 4

5 > SQRT 13

ASSUME X = 16 Y = 9

7>5

ASSUME X= 1/4 , Y = 1/9

1/2+ 1/3 = 5/6 TO SQRT13/36 = 3.X/6 APPRPX 0.5

MY ANSWER IS C