If the product of five numbers in G.P is 1024, then the middle number is 

A) 2

B) 8 

C) 4 

D) 16

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1 Answers

Correct option is (C) 4

Let \(\frac a{r^2},\frac ar,a,ar,ar^2\) be required 5 numbers in G.P.

Given that product of these 5 numbers is 1024.

\(\therefore\) \(\frac a{r^2}.\frac ar.a.ar.ar^2=1024\)

\(\Rightarrow a^5=1024=2^{10}\)

\(=(2^2)^5=4^5\)

\(\Rightarrow\) a = 4

Hence, middle number is a = 4.

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