$A$ person scores $45 \%$ of the total marks in the exam and still fails by $40$ marks. The passing percentage of the exam is $55 \%$. What is the maximum marks of the exam?

Five-ninths of a number is equal to $25$ per cent of the second number. The second number is equal to one-fourth of the third number. The value of the third number is $2960$. What is $30$ per cent of the first number?

Two-fifths of one-third of three-seventh of a number is $15$. What is $40$ per cent of that number?

$A$ pharmaceutical company received $Rs. 3$ million in royalties on the first $Rs. 20$ million in sales of the generic equivalent of one of its products and then $Rs. 9$ million in royalties on the next $Rs. 108$ million in sales. By approximately what percent did the ratio of royalties to sales decrease from the first $Rs. 20$ million in sales to the next $Rs. 108$ million in sales?

$860\%$ of $50 + 50\%$ of $860 = ?$

$A$ district has $64000$ inhabitants. If the population increases at the rate of $2 \frac{1}{2} \%$ per annum,then the number of inhabitants at the end of $3$ years will be...