The cost price of $20$ articles is the same as the selling price of $x$ articles. If the profit is $25 \%$,then the value of $x$ is:

Ajit calculates his profit percentage on the selling price,whereas Rohit calculates his on the cost price. They find that the difference between their profits is $Rs. 100$. If the selling price for both of them is the same and both of them get a $25\%$ profit,find their selling price (in $Rs.$).

$A$ person earns $15 \%$ on an investment but loses $10 \%$ on another investment. If the ratio of the two investments is $3:5$,what is the gain or loss percentage on the two investments taken together (in $\%$)?

Ram purchases a chair at $Rs. 70$ and spends $Rs. 17$ on its repair and $50$ paise on cartage. If he sells the chair at $Rs. 100$,then his approximate profit percentage will be?

$A$ fruit vendor buys $10$ bananas for $Rs. 14$ and sells them at $12$ for $Rs. 15$. Find his percentage gain or loss.

$A$ trader marked his goods at $20 \%$ above the cost price. He sold half the stock at the marked price,one quarter at a discount of $20 \%$ on the marked price,and the rest at a discount of $40 \%$ on the marked price. What is his total gain percentage?