If xy > 0, 1/x + 1/y = 4, and 1/xy = 6, then (x+y)/2 = ?

If xy > 0, 1/x + 1/y = 4, and 1/xy = 6, then (x+y)/2 = ?

Quiz

Answer/Solution

1/3

Steps/Work

(1/X+1/Y)=4 canbe solved as {(x+y)/xy}=6. Substituting for 1/xy=6, we get
x+y=4/6
==> (x+y)/2= 4/(6*2)=1/3.
D