If the Arithmetic Mean $(AM)$ $= 16$ and the Harmonic Mean $(HM)$ $= \frac{63}{4}$ for any two numbers,what will be the Geometric Mean $(GM)$?

If $a, b, c \in \mathbb{R}^+$ are such that $2a, b, 4c$ are in $A.P.$ and $c, a, b$ are in $G.P.$,then:

The product of $n$ positive numbers is $1$. The sum of these numbers cannot be less than what value?

For what value of $m$ is $\frac{a^{m+1}+b^{m+1}}{a^{m}+b^{m}}$ the arithmetic mean of $a$ and $b$?

Let the first three terms $2, p$ and $q$,with $q \neq 2$,of a $G.P.$ be respectively the $7^{\text{th}}$,$8^{\text{th}}$ and $13^{\text{th}}$ terms of an $A.P.$ If the $5^{\text{th}}$ term of the $G.P.$ is the $n^{\text{th}}$ term of the $A.P.$,then $n$ is equal to

What is the minimum value of the sum of the real numbers $a^{-5}, a^{-4}, 3a^{-3}, 1, a^8$,and $a^{10}$ where $a > 0$?