ABC26GN0985 · Simplification

Subject: General Aptitude · Chapter: Simplification · Exam: 2007 · Marks: · Difficulty:

If $x+y=15$ and $x y=56$, then what is the value of $x^{2}+y^{2}$ ?

(a)110

(b)113

(c)121

(d)Cannot be determined

(e)None of these

Answer

Answer (as printed): B

Explanation

$x+y=15 \Rightarrow(x+y)^{2}=(15)^{2}=225$ $$\begin{aligned} & \Rightarrow x^{2}+y^{2}+2 x y=225 \\ & \Rightarrow x^{2}+y^{2}=225-2 x y=225-2 \times 56 \\ & =225-112=113 . \end{aligned}$$

Explanation as extracted from the printed page; notation may be imperfect.

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