The sum of a number and its square is 240. The number is :

(a) 12
(b) 14
(c) 15
(d) 16

Anurag Mishra Professor Asked on 19th January 2016 in Maths.
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  • 1 Answer(s)

    Answer: (c) 15 

    Explanation:-
    Let the number be X. 

    The sum of a number and its square is 240. 
    Then, X^2 + X = 240
     X^2 + X – 240 = 0 
    X^2 + 16 X – 15 X – 240 = 0 
    X (X + 16) – 15 (X  + 16) = 0 
    (X + 16) (X – 15) = 0
    X – 15 = 0 
    X = 15

    Then, the number will be 15. 

    Hence, the correct answer is option (c) 15.

    Anurag Mishra Professor Answered on 22nd January 2016.
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