Nitin ranks eighteenth from the top in a class of $49$ students. What is his rank from the last?

To find a person's rank from the bottom/last end when their rank from the top/starting end is given, we use the formula:
$$\text{Rank from Last}=(\text{Total number of students}-\text{Rank from Top})+1$$

Given parameters:

* Total students = $49$
* Rank from Top = $18$

Substituting the values:

$$\text{Rank from Last}=(49-18)+1$$

$$\text{Rank from Last}=31+1=32$$

Nitin's rank from the last is $32^{\text{nd}}$.