If $G.M. = 18$ and $A.M. = 27$,then $H.M.$ is

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

Three non-zero real numbers form an $A.P.$ and the squares of these numbers taken in the same order form a $G.P.$ Then the number of all possible common ratios of the $G.P.$ is

If the $p^{th}, q^{th}, r^{th}$ and $s^{th}$ terms of an $A.P.$ are in $G.P.$,then $(p - q), (q - r), (r - s)$ will be in:

If $a^2(b + c), b^2(c + a), c^2(a + b)$ are in Arithmetic Progression $(AP)$,then $a, b, c$ are in which progression?

Let $E = x^{2017} + y^{2017} + z^{2017} - 2017xyz$ (where $x, y, z \geq 0$),then the least value of $E$ is