Q268 / 270 · NDA 2011 (Phase 2) · Mathematics

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

  • A
    $10$
  • Correct answer
    B
    $20$
  • C
    $40$
  • D
    $70$

Solution

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

Hence, the correct answer is option: 'B'.

Relevant Questions