In a mixture of $60\, L$,the ratio of acid and water is $2:1$. If the ratio of acid and water is to be $1:2$,then the amount of water (in $litres$) to be added to the mixture is:

$A$ tea seller mixes three qualities of tea $T_{1}, T_{2}$,and $T_{3}$ priced at $Rs. 74$ per kg,$Rs. 68$ per kg,and $Rs. 63$ per kg in the ratio of $1:2:4$. He added some more quantity of $T_{1}$ to $4$ kg of this mixture. He sold this new mixture for $Rs. 84$ per kg,thereby making a profit of $20\%$. How much of $T_{1}$ did he mix with the mixture? (in kg)

Milk and water in a mixture are in the ratio $7:5$. When $15 \, L$ of water is added to it,the ratio of milk and water in the new mixture becomes $7:8$. The total quantity of water in the new mixture is........$L$

In what ratio must a person mix three kinds of wheat costing $Rs. 1.20$,$Rs. 1.44$ and $Rs. 1.74$ per $kg$ so that the mixture may be worth $Rs. 1.41$ per $kg$?

Nine litres of water are drawn from a container full of water and it is then filled with milk. Nine litres of mixture are drawn and the container is again filled with milk. The ratio of the quantity of water now left in the container to that of the milk in it is $16:9$. How much liquid does the container hold? (in $litres$)

$A$ cylinder which has the capacity of $8 \text{ litres}$ contains a mixture of oxygen and nitrogen. The volume of oxygen in the cylinder is $16 \%$ of the total volume. $A$ few litres of the mixture is released and an equal amount of nitrogen is added. Then,the same amount of the mixture as before is released and replaced by nitrogen for the second time. As a result,the oxygen content becomes $9 \%$ of the total volume. Find the amount of mixture released each time (in litres).