In what ratio should sugar at ₹ $30$ per $kg$ be mixed with sugar at ₹ $45$ per $kg$ so that on selling the mixture at ₹ $42$ per $kg$ there is a profit of $20 \%$?

$A$ milk vendor has $2$ cans of milk. The first contains $25\%$ water and the rest milk. The second contains $50\%$ water. How much milk should he mix from each of the containers so as to get $12$ litres of milk such that the ratio of water to milk is $3:5$?

$A$ sum of $Rs. 6.40$ is made up of $80$ coins which are either $10$-paise or $5$-paise coins. How many $5$-paise coins are there?

Pure milk costs $16 / L$. After adding water,the milkman sells the mixture at $15 / L$ and thereby makes a profit of $25 \%$. In what respective ratio does he mix milk with water?

In a mixture of milk and water of volume $30 \ L$,the ratio of water and milk is $3:7$. How much quantity of water should be added to the mixture to make the ratio of milk and water $1:2$ (in $L$)?

Aditya,Sonal,and Nutan contributed $Rs. 50,000$ for a business. Aditya contributed $Rs. 4,000$ more than Sonal,and Sonal contributed $Rs. 5,000$ more than Nutan. Out of a total profit of $Rs. 70,000$,how much did Aditya receive? (in $Rs.$)