How often will five bells toll together in one hour if they start together and toll at intervals of $5, 6, 8, 12, 20$ seconds,respectively?

$H.C.F.$ of $\frac{2}{3}, \frac{4}{5}$ and $\frac{6}{7}$ is

$A$ wholesale tea dealer has $408$ kilograms,$468$ kilograms,and $516$ kilograms of three different qualities of tea. He wants to pack all of it into boxes of equal size without mixing the different qualities. Find the capacity of the largest possible box.

Find the greatest number of $4$ digits and the least number of $5$ digits that have $196$ as their $HCF$.

Two pipes of length $1.5\, m$ and $1.2\, m$ are to be cut into equal pieces without leaving any extra length of pipes. The greatest length of the pipe pieces of same size which can be cut from these two lengths will be (in $metre$)

If the $L.C.M.$ and $H.C.F.$ of two expressions are $(x^{2}+6x+8)(x+1)$ and $(x+1)$ respectively, and one of the expressions is $x^{2}+3x+2$, find the other.