In a increasing geometric series, the sum of the second and the sixth term is $\frac{25}{2}$ and the product of the third and fifth term is $25 .$ Then, the sum of $4^{\text {th }}, 6^{\text {th }}$ and $8^{\text {th }}$ terms is equal to
$30$
$26$
$35$
$32$
Three numbers are in $G.P.$ such that their sum is $38$ and their product is $1728$. The greatest number among them is
Which term of the $GP.,$ $2,8,32, \ldots$ up to $n$ terms is $131072 ?$
The sum of infinite terms of the geometric progression $\frac{{\sqrt 2 + 1}}{{\sqrt 2 - 1}},\frac{1}{{2 - \sqrt 2 }},\frac{1}{2}.....$ is
$0.\mathop {423}\limits^{\,\,\,\,\, \bullet \, \bullet \,} = $
If $a,\;b,\;c$ are in $G.P.$, then