The price of an article was increased by $r \%$. Later,the new price was decreased by $r \%$. If the latest price was $₹ 1$,then the original price was:

The value of a machine is $Rs$ $6250$. It decreases by $10 \%$ during the first year,$20 \%$ during the second year,and $30 \%$ during the third year. What will be the value of the machine after $3$ years?

Two-thirds of three-fourths of one-fifth of a number is $15$. What is $30$ per cent of that number?

$A$ 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.

Two tailors $X$ and $Y$ are paid a total of ₹ $550$ per week by their employer. If $X$ is paid $120$ percent of the sum paid to $Y$,how much is $Y$ paid per week?

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 $\%$)?