What is $15$ percent of Rs. $34$?

If the price of a shirt is increased by $25 \%$ and then decreased by $30 \%$,then what will be the net effect?

How much pure alcohol has to be added to $400 \text{ ml}$ of a solution containing $15 \%$ alcohol to change the concentration of alcohol in the mixture to $32 \%$?

The value of a machine depreciates at the rate of $10 \%$ every year. It was purchased $3$ years ago. If its present value is $₹ 8748$,its purchase price was:

$x \%$ of $y + ? \%$ of $x = x \%$ of $(x + y)$

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 $\%$)