If $a_1, a_2...,a_n$ an are positive real numbers whose product is a fixed number $c$ , then the minimum value of $a_1 + a_2 +.... + a_{n - 1} + 2a_n$ is
$n(2c)^{1/n}$
$(n + 1)c^{1/n}$
$2nc^{1/n}$
$(n + 1)(2c)^{1/n}$
Consider two positive numbers $a$ and $b$ . If arithmetic mean of $a$ and $b$ exceeds their geometric mean by $\frac{3}{2}$ and geometric mean of $a$ and $b$ exceeds their harmonic mean by $\frac{6}{5}$ , then the absolute value of $(a^2 -b^2)$ is equal to
The minimum value of the sum of real numbers $a^{-5}, a^{-4}, 3 a^{-3}, 1, a^8$ and $a^{10}$ with $a>0$ is
If $a, b$ are positive real numbers such that the lines $a x+9 y=5$ and $4 x+b y=3$ are parallel, then the least possible value of $a +b$ is
If the ratio of two numbers be $9:1$, then the ratio of geometric and harmonic means between them will be
The geometric mean of two numbers is $6$ and their arithmetic mean is $6.5 $. The numbers are