ABC26GN1487 · Square Roots and Cube Roots
Subject: General Aptitude · Chapter: Square Roots and Cube Roots · Exam: · Marks: · Difficulty:
$(\sqrt{63}+\sqrt{252}) \times(\sqrt{175}+\sqrt{28})=$ ? [IBPS-RRB Office Assistant (Online) Exam, 2015]
(a)$16 \sqrt{7}$
(b)441
(c)16
(d)$7 \sqrt{7}$
Answer
Explanation
Given $(\sqrt{63}+\sqrt{252}) \times(\sqrt{175}+\sqrt{28})$ $$\begin{aligned} & =(\sqrt{63}+\sqrt{4 \times 63}) \times(\sqrt{25 \times 7}+\sqrt{4 \times 7}) \\ & =(\sqrt{7 \times 9}+\sqrt{4 \times 9 \times 7}) \times(\sqrt{5 \times 5 \times 7}+\sqrt{2 \times 2 \times 7}) \\ & =(3 \sqrt{7}+6 \sqrt{7}) \times(5 \sqrt{7}+2 \sqrt{7}) \\ & =9 \sqrt{7} \times 7 \sqrt{7}=441 \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.
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