Swarna is ranked sixteenth from the top and sixth from the bottom of a class. How many students are there in the class?

The formula to find the total number of students when the position of a single person is given from both ends is:
$$\text{Total}=\text{Rank from Top}+\text{Rank from Bottom}-1$$

Given parameters for Swarna:

* $\text{Rank from Top}=16$
* $\text{Rank from Bottom}=6$

Substitute the values:

$$\text{Total}=16+6-1=22-1=21$$

There are $21$ students in the class.