The $LCM$ of two prime numbers $x$ and $y$ $(x > y)$ is $161$. Find the value of $(3y - x)$.

In four consecutive prime numbers that are in ascending order,the product of the first three is $385$ and that of the last three is $1001$. The largest given prime number is

The product of two numbers is $2028$ and their $HCF$ is $13$. The number of such pairs is

Find the smallest number of five digits exactly divisible by $12, 16, 18$ and $27$.

The $HCF$ of two numbers is $8$. Which one of the following can never be their $LCM$?

$L.C.M.$ and $H.C.F.$ of two numbers $x$ and $y$ are $315$ and $3,$ respectively. If $x+y=36,$ the value of $\frac{1}{x}+\frac{1}{y}$ is