In two types of brass,the ratios of Copper to Zinc are $8:3$ and $15:7$ respectively. If the two types of brass are melted and mixed in the ratio $5:2$,a new type of brass is obtained. The ratio of Copper to Zinc in this new type of brass is:

$8$ litres are drawn from a cask full of wine and is then filled with water. This operation is performed three more times. The ratio of the quantity of wine now left in the cask to that of the water is $16$:$65$. How much wine did the cask hold originally? (in litres)

Gold is $21$ times as heavy as water and copper is $11$ times as heavy as water. In what ratio should these metals be mixed so that the mixture may be $17$ times as heavy as water?

$A$ man has $60$ pens. He sells some of these at a profit of $12 \%$ and the rest at $8 \%$ loss. On the whole,he gets a profit of $11 \%$. How many pens were sold at $12 \%$ profit?

$A$ can contains a mixture of two liquids $A$ and $B$ in the ratio $4:7$. When $6 \text{ litres}$ of the mixture are drawn off and the can is filled with liquid $B$,the ratio of $A$ and $B$ becomes $3:7$. How many litres of liquid $A$ were contained in the can initially?

In what ratio must a grocer mix two varieties of pulses costing ₹ $15$ and ₹ $20$ per $kg$ respectively so as to get a mixture worth ₹ $16.5/kg$?