If five G.M.’s are inserted between 486 and 2/3 then fourth G.M. … - Vidyadip

MCQ

If five $G.M.’s$ are inserted between $486$ and $2/3$ then fourth $G.M.$ will be

A
$4$
✓
$6$
C
$12$
D
$-6$

✓

Answer

Correct option: B.

$6$

b
(b) Let ${G_1},{G_2},{G_3},{G_4},{G_5}$ be the $G.M.’s$ are inserted between $486$ and $2/3$.

So total terms are $7$.

${T_n} = a{r^{n - 1}}$

==> $2/3 = 486$${(r)^6}$

$ \Rightarrow r = 1/3$

Hence $4^{th}$ $G.M.$ will be,

${T_5} = a{r^4} = 486\,{(1/3)^4} = 6$.

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