In an examination out of $480$ students,$85 \%$ of the girls and $70 \%$ of the boys passed. How many boys appeared in the examination if the total pass percentage was $75 \% ?$

$A$ 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)

In a mixture of $75 \ L$,the ratio of milk to water is $2:1$. The amount of water to be further added to the mixture so as to make the ratio of the milk to water $1:2$ will be (in $L$):

In what ratio should coffee powder costing ₹ $2500$ per $kg$ be mixed with coffee powder costing ₹ $1500$ per $kg$ so that the cost of the mixture is ₹ $2250$ per $kg$?

In what proportion must tea worth $75$ paise per packet be mixed with tea worth ₹$5.50$ per packet so that the mixture may cost ₹$4.50$ per packet?

Two vessels contain milk and water in the ratio $3:2$ and $7:3$. Find the ratio in which the contents of the two vessels have to be mixed to get a new mixture in which the ratio of milk and water is $2:1$.