The population of a town increases by $12 \%$ during the first year and decreases by $10 \%$ during the second year. If the present population is $50400$,what was it $2$ years ago?

Aditya's monthly salary is $15\%$ more than Sanjay's monthly salary. If Aditya's monthly salary is $17250$,what is Sanjay's annual salary?

The length of a rectangle increases by $20 \%$ and the breadth by $30 \%$. Then the perimeter of the rectangle will increase by:

To attract more visitors,the zoo authority announces a $20 \%$ discount on every ticket,which costs $25 \ p$. For this reason,the sale of tickets increases by $28 \%$. Find the percentage of increase in the number of visitors.

What per cent of a day is $3$ hours?

In the laptop market,only three competitors (Lenovo,Apple,and Samsung) exist. Last year,the sales of Apple laptops were $10 \%$ more than Lenovo. This year,both the firms Lenovo and Apple increased their respective sales by $20 \%$. This year,the sales of the firm Apple are five times that of Samsung. What percentage of the total market sales did Samsung account for last year,if the total sales remained constant over the two-year period (in $\%$)?