How many $kg$ of sugar costing ₹ $5.75$ per $kg$ should be mixed with $75 \, kg$ of cheaper sugar costing ₹ $4.50$ per $kg$,so that the mixture is worth ₹ $5.50$ per $kg$?

Find the ratio in which rice at $Rs. 7.20$ per $kg$ should be mixed with rice at $Rs. 5.70$ per $kg$ to produce a mixture worth $Rs. 6.30$ per $kg$.

$A$ mixture of a certain quantity of milk with $16$ litres of water is worth $90$ $P$ per litre. If pure milk is worth $Rs. 1.08$ per litre,how much milk is there in the mixture? (in Litres)

Two alloys contain tin and iron in the ratio of $1:2$ and $2:3$. If the two alloys are mixed in the proportion of $3:4$ respectively (by weight),the ratio of tin and iron in the newly formed alloy is:

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 an examination out of $900$ students,$85 \%$ of the boys and $70 \%$ of the girls passed. How many girls appeared in the examination,if the total pass percentage was $75 \% ?$