$8000 \div 16 - 200 = ? \times 6$

$A$ mason can build a wall in $70$ hours. After $7$ hours,he takes a break. What fraction of the wall is yet to be built?

If the two digits of the age of Mr. Manoj are reversed,then the new age so obtained is the age of his wife. $\frac{1}{11}$ of the sum of their ages is equal to the difference between their ages. If Mr. Manoj is older than his wife,then find the difference between their ages.

There is a number consisting of two digits. The digit in the units place is twice that in the tens place,and if $2$ is subtracted from the sum of the digits,the difference is equal to $1/6^{\text{th}}$ of the number. The number is:

The numerator of a fraction is the product of two numbers. One of the numbers is greater than the other by $2$. The greater number is smaller than the denominator $D = 7+c$ (where $c > -7$ is a constant). If the fraction is $f(x) = \frac{(x-2)x}{x+k}$ (where $x$ is the greater number),find the minimum value of the fraction.

$(\sqrt{9})^{3} \times (\sqrt{81})^{5} \div 27^{2} = 3^{?}$