ABC26GN3039 · Ratio and Proportion

Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: · Marks: · Difficulty:

The mean proportional between $(3+\sqrt{2})$ and ( $12-\sqrt{32})$ is
(a)$\sqrt{7}$
(b)$2 \sqrt{7}$
(c)6
(d)$\frac{15-3 \sqrt{2}}{2}$
Answer
Answer (as printed): B
Explanation
Required mean proportional $=\sqrt{(3+\sqrt{2})(12-\sqrt{32})}$ $$\begin{aligned} & =\sqrt{(3+\sqrt{2})(12-4 \sqrt{2})} \\ & =\sqrt{36-8}=\sqrt{28}=2 \sqrt{7} . \end{aligned}$$

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

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