$60\, kg$ of an alloy $A$ is mixed with $100\, kg$ of alloy $B.$ If alloy $A$ has lead and tin in the ratio $3:2$ and alloy $B$ has tin and copper in the ratio $1:4,$ the amount of tin in the new alloy is (in $kg$)

Gold is $19$ times as heavy as water and copper is $9$ times. In what ratio should these metals be mixed so that the mixture may be $15$ times as heavy as water?

How much tea at $Rs. 4$ a $kg$ should be added to $15 \, kg$ of tea at $Rs. 10$ per $kg$ so that the mixture is worth $Rs. 6.50$ a $kg$? (in $kg$)

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 $L$)?

$A$ mixture contains $80 \%$ acid and the rest water. What part of the mixture should be removed and replaced by the same amount of water to make the ratio of acid to water $4:3$?

$A$ jar contained a mixture of two liquids $A$ and $B$ in the ratio $3 : 2.$ When $5$ litres of the mixture was taken out and $5$ litres of liquid $B$ was poured in the jar,this ratio became $2 : 3.$ The quantity of liquid $A$ contained in the jar initially was (in litres).