Varun's expenditures and savings are in the ratio of $4:1$. His income increases by $20\%$. If his savings increase by $12\%$, by how much percentage should his expenditure increase?

If $2 \, kg$ of metal,of which $\frac{1}{3}$ is zinc and the rest is copper,is mixed with $3 \, kg$ of metal,of which $\frac{1}{4}$ is zinc and the rest is copper,what is the ratio of zinc to copper in the mixture?

$A$ trader has $50 \text{ kg}$ of rice,a part of which he sells at $10 \%$ profit and the rest at $5 \%$ loss. He gains $7 \%$ on the whole. What is the quantity sold at $10 \%$ gain and $5 \%$ loss? (in $\text{kg}$)

$A$ container contains $50 \, \text{litres}$ of milk. From this container $5 \, \text{litres}$ of milk was taken out and replaced by water. This process was repeated further two times. How much milk is now contained by the container? (in $\text{litres}$)

$A$ person has a chemical of ₹ $25$ per litre. In what ratio should water be mixed in that chemical,so that after selling the mixture at ₹ $20$ per litre,he may get a profit of $25 \%$?

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 $L$):