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

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

If $a, x, y, z, b$ are in Arithmetic Progression ($A$.$P$.) such that $x + y + z = 15$,and if $a, x, y, z, b$ are in Harmonic Progression ($H$.$P$.) such that $1/x + 1/y + 1/z = 5/3$,find the values of $a$ and $b$.

If $a, b, c$ are in both Arithmetic Progression $(A.P.)$ and Geometric Progression $(G.P.)$,then......

The product of $n$ positive numbers is unity. Their sum is

The difference between two numbers is $48$ and the difference between their arithmetic mean and geometric mean is $18$. The larger of the two numbers is: