NDA 2016 Maths · Mathematics · Sequences and Series · medium

In a geometric progression of positive terms, the third term is 12 and the sixth term is 96. The eighth term is

Single correct option

In a geometric progression of positive terms, the third term is

12

and the sixth term is

96

. The eighth term is

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Answer: (D) $384$

Dividing,

r^3=96/12=8

, so

r=2

and

a=12/r^2=3

. The eighth term is

ar^7=3\times128=384

. Writing

ar^8

gives 768, and starting from the sixth term but multiplying by only

r

once gives 192.

Original question written in the NDA 2016 Maths pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake