If the price of gold increases by $30 \%$,find by how much the quantity of ornaments must be reduced so that the expenditure may remain the same as before?

Sweta invested $Rs. 10,000$ in a scheme exactly three years ago. The value of the investment increased by $10\%$ during the first year,increased by $5\%$ during the second year,and decreased by $10\%$ during the third year. What is the value of the investment today?

If the length of a rectangle is increased by $20 \%$ and its breadth is decreased by $10 \%$,what will be the impact on its perimeter?

At an election,a candidate got elected by fetching $63 \%$ of the total votes. If $54982$ voters did not vote in favour of the elected candidate,what was the total number of votes polled?

Aditya's salary is $80\%$ of Amit's salary and $120\%$ of Rajiv's salary. What is Amit's salary if Rajiv's salary is $30,000$ (in $,000$)?

There are $1400$ students in the school. $25 \%$ of them wear spectacles and $\frac{2}{7}$ of those who wear spectacles are boys. How many girls in the school wear spectacles?