If x + y = 6 and x2 + y2 = 30, then find the product of both the variables ‘x’ and ‘y’.

I have a problems on MATH, My questions is –
If x + y = 6 and x2 + y2 = 30, then find the product of both the variables ‘x’ and ‘y’.

My 4 answers options are –
a. 6
b. 36
c. 2
d. 5
e. 3

Which is the correct answer? please explain.
Please help me by salving this GMAT Questions.
Thanks.

Default Asked on October 13, 2017 in GMAT.
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1 Answer(s)

    Thanks for your questions, your question is –

    If x + y = 6 and x2 + y2 = 30, then find the product of both the variables ‘x’ and ‘y’.

    Correct answer: e

    Now read the details Explanation for your given questions clarifications:
    We know the standard algebraic formula for (x+y)2
    (x+y)2 = x2 + 2xy + y2
    Now, according to the information given in the question, x + y = 6 and x2 + y2 = 30
    Substituting these values in above equation, we get,
    (6)2 = 30 + 2xy
    ∴ 36 – 30 = 2xy
    ∴ 6 = 2xy
    ∴ xy = 3
    Hence, the correct answer is option= e.

    If you like my answer, share this to your friends.

    Silver Answered on October 16, 2017.
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