The price of cooking oil has increased by $25 \%$. 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 (in $\%$)

The difference between a number and its two-fifth is $610$. What is $10\%$ of that number?

When a number is increased by $216$,it becomes $140\%$ of itself. What is the number?

In a school there are $1500$ students,$44 \%$ of whom are girls. The monthly fee of each boy is $₹ 540$ and the fee of each girl is $25 \%$ less than that of a boy. What is the sum of the monthly fees of all the boys and girls?

Mr. Sarang invests $6 \%$ of his monthly salary,i.e.,$Rs.$ $2,100$ on insurance policies. He also invests $8 \%$ of his monthly salary on Family Mediclaim Policies and another $9 \%$ of his salary on $NSCs$. What is the total annual amount invested by Mr. Sarang?

The income of a company increases $20 \%$ per annum. If its income is $Rs$ $42664000$ in the year $1999$,what was its income in the year $1997$?