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NDA 2011
Exam
NDA
Year
2011
Subject
Mathematics
Chapter
Sequences and Series

NDA 2011 · Mathematics · Sequences and Series

What is the geometric mean of 10,40 and 20 ?

What is the geometric mean of 10,40 and 20?20 ?

Options

  1. A1010
  2. B2020
  3. C4040
  4. D7070

Correct answer

B. 2020

Step-by-step solution

Geometric mean of 10,40 and 20is20 is Here n=3∴ G.M. =10×40×203=80003=(203)13=20.\begin{aligned} \text{ Here } \quad n & =3 \\ \therefore \quad \text{ G.M. } & =\sqrt[3]{10 \times 40 \times 20}=\sqrt[3]{8000} \\ & =\left(20^3\right)^{\frac{1}{3}}=20. \end{aligned}$$
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