Find all pairs of consecutive odd positive integers,both of which are smaller than $18$,such that their sum is more than $20$.

In a manufacturing company,the cost and revenue functions of a product are given by $C(x) = 500 + \frac{5}{2}x$ and $R(x) = 3x$,where $x$ is the number of items produced and sold. How many items must be sold to realize no profit or loss? Is there any profit?

To receive grade $A$ in a course,one must obtain an average of $90$ marks or more in five examinations (each of $100$ marks). If Sunita's marks in the first four examinations are $87, 92, 94,$ and $95,$ find the minimum marks that Sunita must obtain in the fifth examination to get grade $A$ in the course.

The marks scored by Mohan in two tests were $62$ and $48$. Find the minimum marks he should score in the third test to have an average of at least $60$ marks.

If $x$ is real and satisfies $x + 2 > \sqrt{x + 4}$,then

For a positive integer $n$,the inequality $10^{n - 2} > 81n$ holds true if: