ABC26GN0181 · Number System

Subject: General Aptitude · Chapter: Number System · Exam: · Marks: · Difficulty:

$\left\{(476+424)^{2}-4 \times 476 \times 424\right\}=$ ?
(a)2906
(b)3116
(c)2704
(d)2904
(e)None of these
Answer
Answer (as printed): C
Explanation
$$\begin{aligned} (476+424)^{2}-4 \times 476 \times 424=(a+b)^{2}-4ab & =(a-b)^{2}, \\ \text{where } a=476 \text{ and } b=424 & =(476-424)^{2}=(52)^{2}=(50+2)^{2} \\ & =(50)^{2}+2^{2}+2 \times 50 \times 2 \\ & =(2500+4+200)=2704. \end{aligned}$$

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

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