If x + y = 5 and xy = 6, then 1/x + 1/y = ?

Question

If  x + y = 5  and  xy = 6 , then  \frac{1}{x} + \frac{1}{y} =  ?

(A) 1/6
(B) 1/5 
(C) 5/6 
(D) 6/5
(E) 5

Momsspaghetti · Answer

1/x + 1/y = x+y/ xy

X+Y = 5 and xy = 6 (Given)

OA : C

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gmatophobia · Answer

\frac{1}{x} + \frac{1}{y} =

Taking xy as the LCM

\frac{ x + y }{ xy}  =  \frac{5}{6}

Option C

RogueTruck · Answer

You can rearrange the second equation to get x=6/y and y=6/x

Substituting both into the first equation gets you 6/y + 6/x = 5

Then divide both sides by 6 to get 1/y + 1/x = 5/6

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