NDA 2023 Maths · Mathematics · Sequences and Series · medium

The harmonic mean of two positive numbers is 4.8 and their arithmetic mean is 5. Their geometric mean is

Single correct option

The harmonic mean of two positive numbers is

4.8

and their arithmetic mean is

5

. Their geometric mean is

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Answer: (D) $2\sqrt6$

For two positive numbers

G^2=A\cdot H=5\times4.8=24

, so

G=\sqrt{24}=2\sqrt6\approx4.90

. This lies between

H=4.8

and

A=5

as it must. The number

24

G^2

, not

G

, and the average of

A

and

H

(

4.9

) is only an approximation, not the exact value.

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