What will be the duplicate ratio of $2: 7$?

Out of the number of qualified candidates from State $P$ in $2008,$ the respective ratio of male and female candidates is $11: 7.$ If the number of female qualified candidates from State $P$ in $2008$ is $126,$ what is the total number of qualified candidates (both male and female) from State $P$ in $2008?$

If $50$ fewer candidates had applied and $25$ fewer had been selected,the ratio of selected to unselected candidates would have been $9:4$. How many candidates had applied if the initial ratio of selected to unselected candidates was $2:1$?

Two numbers are in the ratio $3: 5$. If each number is increased by $10$,the ratio becomes $5: 7$. The numbers are:

Three vessels having volumes in the ratio of $2: 3: 5$ are full of a mixture of water and milk. In the first vessel,the ratio of water and milk is $1: 3$,in the second $2: 3$,and in the third vessel,$2: 5$. If all the three vessels are poured into a large container,what is the resulting ratio of milk and water?

The sum of two numbers is $25$ and their difference is $7 \frac{1}{2}$. Find the ratio of the numbers.