$85 \, L$ of a mixture contains milk and water in the ratio $27: 7$. How much more water (in $L$) is to be added to get a new mixture containing milk and water in the ratio $3: 1$?

The sum of three numbers is $98$. If the ratio of the first to the second is $2:3$ and that of the second to the third is $5:8$,then the second number is:

If $A: B = 3: 4$ and $B: C = 8: 9$,then find the value of $A: B: C$.

In an army selection process,the ratio of selected to unselected candidates was $4:1$. If $90$ less had applied and $20$ less were selected,the ratio of selected to unselected candidates would have been $5:1$. How many candidates had applied for the process?

Find the third proportional to the numbers $4$ and $42$.

The ratio of the ages of a man and his wife is $4:3$. After $4$ years,this ratio will be $9:7$. If at the time of marriage,the ratio was $5:3$,then how many years ago were they married?