ABC26GN1215 · Simplification

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

$\frac{(13)^{3}+7^{3}}{(13)^{2}+7^{2}-?}=20$

(a)6

(b)20

(c)91

(d)None of these

Answer

Answer (as printed): C

Explanation

Let $\frac{13^{3}+7^{3}}{13^{2}+7^{2}-x}=20$. Then, $\frac{13^{3}+7^{3}}{13+7}=13^{2}+7^{2}-x$ $$\begin{aligned} & \Leftrightarrow 13^{2}+7^{2}-13 \times 7=13^{2}+7^{2}-x \\ & \Leftrightarrow x=13 \times 7=91 . \end{aligned}$$

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

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