What must be added to each term of the ratio $2:5$ so that it may equal to $5:6$?

Before a war,the ratio of tanks to planes in an army was $5:3$. During the war,$1000$ tanks were destroyed and $800$ planes were destroyed. The ratio of tanks to planes became $2:1$. What is the number of tanks after the war?

$85 \, L$ 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 $3: 1$?

Hitesh is $40$ years old and Ronnie is $60$ years old. How many years ago was the ratio of their ages $3:5$?

The ratio of the incomes of $A, B$ and $C$ is $3: 7: 4$ and the ratio of their expenditures is $4: 3: 5$. If in the income of $Rs. 2400$, $A$ saves $Rs. 300$, then the savings of $B$ and $C$ respectively are:

$A$ bag contains $10$-paise and $25$-paise coins in the ratio of $17:6$. If the total money in the bag is $Rs. 112$,the number of $10$-paise coins is: