Starting with $8000$ workers,the company increases the number of workers by $5 \%$,$10 \%$,and $20 \%$ at the end of the first,second,and third year,respectively. The number of workers in the fourth year is:

If $25 \%$ of a number is subtracted from a second number,the second number reduces to its five-sixths. What is the ratio of the first number to the second number?

In a History examination,the average for the entire class was $80$ marks. If $10 \%$ of the students scored $95$ marks and $20 \%$ scored $90$ marks,what was the average marks of the remaining students of the class?

Sashi has $Rs. 90000$ with him. He purchases a mobile,an iPad,and a laptop for $Rs. 15000$,$Rs. 13000$,and $Rs. 35000$ respectively and puts the remaining money in his bank account which pays $15 \%$ per annum compound interest. After $2$ years,he sells off the three items at $80 \%$ of their original price and also withdraws his entire money from the bank by closing the account. What is the total percentage change in his assets (in $\%$)?

Amit donated $20\%$ of his income to a school and deposited $20\%$ of the remainder in his bank. If he has $₹ 12800$ now,what is the income (in $₹$) of Amit?

$A$ merchant has announced a $25 \%$ rebate on the prices of ready-made garments at the time of sale. If a purchaser needs to have a total rebate of $₹ 400$,then how many shirts,each costing $₹ 320$,should they purchase?