Mixture and Alligation Questions

In what ratio must the two types of tea at $\text{₹ }180\text{/kg}$ and $\text{₹ }280\text{/kg}$ respectively be mixed so that the obtained mixture sold at $\text{₹ }320\text{/kg}$ earns a profit of $20\%$?

In a glass, milk and water are mixed in the ratio of $3:5$ and in another glass they are mixed in the ratio of $6:1$. In what ratio should the contents of the two glasses be mixed together so that the new mixture contains milk and water in the ratio of $1:1$?

In a $2025\text{ litre}$ mixture of milk and water, the ratio of milk to water is $12:13$. To get a new mixture containing milk and water in the ratio of $12:15$, the amount of water to be added is: