Find the highest common factor of $36$ and $84.$

The product of two numbers is $4212$ and their $HCF$ is $9$. Find the possible pair of numbers.

Find the maximum possible length which can be used to measure exactly the lengths $6 \, m$,$4 \, m \, 75 \, cm$,and $10 \, m \, 25 \, cm$. (in $, cm$)

Three different containers contain different quantities of a mixture of milk and water,measuring $403 \ kg$,$434 \ kg$,and $465 \ kg$. What is the largest measure that can measure all these quantities exactly? (in $kg$)

Three numbers which are co-prime to each other are such that the product of the first two is $551$ and that of the last two is $1073$. The sum of the three numbers is:

Find the least number which is a multiple of $31$ and when divided by $15, 24$ and $32$ leaves the remainders $2, 11$ and $19$,respectively.