Question : Gaurav ranks eighteenth from the top in a class. What is his rank from the last?

Statements :
I. There are 47 students in the class.
II. Jatin who ranks 10th in the same class, ranks 38th from the last.

Explanation:-

From I, we conclude that in a class of 47 students, Gaurav ranks 18th from the top and hence 30th from the last.
From II, we conclude that there are 9 students above and 37 students below Jatin in rank. Thus, there are (9 + 1 + 37) = 47 students in the class.
So, Gaurav who ranks 18th from the top, is 30th from the last.