What fraction is $0.6 \%$?

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 $\%$)?

$A$ person's salary has increased from $Rs. 7200$ to $Rs. 8100$. What is the percentage increase in his salary (in $\%$)?

In an examination,there are $1000$ boys and $800$ girls. $60 \%$ of boys and $40 \%$ of girls passed. The percentage of candidates that failed is: (in $\%$)

$A$ student has to secure $15\%$ marks to pass the examination. If he gets $80$ marks and fails by $70$ marks,find the maximum marks set for the examination.

In a class of $50$ students and $5$ teachers,each student received sweets equal to $12 \%$ of the total number of students,and each teacher received sweets equal to $20 \%$ of the total number of students. How many sweets were there in total?