In what ratio should two varieties of tea,one costing ₹$25$ per $kg$ and the other costing ₹$30$ per $kg$,be blended to produce a blended variety of tea worth ₹$28$ per $kg$?

In what proportion must a grocer mix sugar at ₹ $12$ per $kg$ and ₹ $7$ per $kg$ so as to make a mixture worth ₹ $8$ per $kg$?

$A$ barrel contains a mixture of wine and water in the ratio $3:1$. How much fraction of the mixture must be drawn off and substituted by water so that the ratio of wine and water in the resultant mixture in the barrel becomes $1:1$?

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:

$300$ $gm$ of sugar solution contains $40 \%$ sugar. How much sugar (in $gm$) should be added to make the concentration $50 \%$ in the solution?

There are two containers of equal capacity. The ratio of milk to water in the first container is $3:1$,and in the second container,it is $5:2$. If they are mixed,the ratio of milk to water in the mixture will be: