Question : Find the fourth proportion of the numbers $\frac{1}{3}{rd}$ of 15, $\frac{4}{5}{th}$ of 25, $\frac{3}{7}{th}$ of 35:

Question : What is the value of $x$?
$\frac{3}{2}× \frac{7}{3} ÷ \frac{7}{6}+\frac{1}{4}=\frac{1}{x}$

Question : Three numbers are such that the average of the first two numbers is 2, the average of the last two numbers is 3 and the average of the first and the last numbers is 4. What is the average of the three numbers?

Question : The value of $2 \frac{3}{5} \div\left[2 \frac{1}{3} \div\left\{4 \frac{1}{3}-\left(2 \frac{1}{2}+\frac{2}{3}\right)\right\}\right]$ is equal to:

Question : If $\frac{x}{y}=\frac{4}{5}$, then the value of $(\frac{4}{7}+\frac{2y–x}{2y+x})$ is: