What is the $40 \%$ of $50 \%$ of $\frac{3}{4}$ of $3200$?

$A$ 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 an election between two candidates,one got $55 \%$ of the total valid votes,and $20 \%$ of the total votes were invalid. If the total number of votes was $7500$,what was the number of valid votes that the other candidate received?

Two numbers are more than the third number by $20 \%$ and $80 \%$ respectively. The first number is what percent of the second number?

If the numerator of a fraction is increased by $120 \%$ and the denominator is also increased by $350 \%$,then the fraction becomes $\frac{11}{27}$. What was the original fraction?

To attract more visitors,the zoo authority announces a $20 \%$ discount on every ticket,which costs $25 \ p$. For this reason,the sale of tickets increases by $28 \%$. Find the percentage of increase in the number of visitors.