Let $x, y, z$ be three non-negative integers such that $x+y+z=10$. The maximum possible value of $x y z+x y+y z+z x$ is
$52$
$64$
$69$
$73$
If $A.M.$ of two terms is $9$ and $H.M.$ is $36$, then $G.M.$ will be
If the arithmetic mean of two numbers $a$ and $b, a>b>0$, is five times their geometric mean, then $\frac{{a + b}}{{a - b}}$ is equal to
If the ratio of $H.M.$ and $G.M.$ of two quantities is $12:13$, then the ratio of the numbers is
Let $a, b$ and $c$ be the $7^{th},\,11^{th}$ and $13^{th}$ terms respectively of a non -constant $A.P.$ If these are also the three consecutive terms of a $G.P.$ then $\frac {a}{c}$ is equal to
If all roots of the equation $x^3 -2ax^2 + 3bx -8$=$0$ are positive, $a$,$b \in R$ , then the minimum value of $b$ is