Sequences and Series 3 Question 13
13.
The third term of a geometric progression is 4 . The product of the first five terms is
(a) $4^{3}$
(b) $4^{5}$
(c) $4^{4}$
(d) None of these
(1982, 2M)
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Answer:
Correct Answer: 13. (b)
Solution:
- Here, $t _3=4 \Rightarrow a r^{2}=4$
$\therefore$ Product of first five terms $=a \cdot a r \cdot a r^{2} \cdot a r^{3} \cdot a r^{4}$
$ =a^{5} r^{10}=\left(a r^{2}\right)^{5}=4^{5} $
