The price of cooking oil has increased by $15 \%$. The percentage of reduction that a family should effect in the use of cooking oil so as not to increase the expenditure on this account is:

$A, B,$ and $C$ shared $Rs. 18500$ such that $A$ received $25\%$ more than $B$ and $B$ received $20\%$ more than $C$. What amount did $A$ receive?

In a test,a candidate secured $468$ marks out of maximum marks $A$. If the maximum marks $A$ were converted to $700$ marks,he would have secured $336$ marks. What were the maximum marks of the test?

Mrs. Jain invests $14 \%$ of her monthly salary,i.e.,$Rs. 7014$ in Insurance Policies. Later she invests $21 \%$ of her monthly salary on Family Mediclaim Policies; also she invests another $6.5 \%$ of her salary on Mutual Funds. What is the total annual amount invested by Mrs. Jain?

The tax on a commodity is diminished by $10 \%$ and its consumption increases by $10 \%$. Find the effect on revenue.

The population of a town increases by $2.5 \%$ annually but decreases by $0.5 \%$ every year due to migration. What will be the net percentage increase in population after $2$ years (in $\%$)?