Rahul ranked 16th from the top and 27th from the bottom in his class. How many students are there in the class?

16th from the top means $15$ students are above Rahul.

27th from the bottom means $26$ students are below Rahul.

Total students $=$ students above $+$ Rahul $+$ students below

$= 15 + 1 + 26$

$= 42$

Shortcut: Total $=$ rank from top $+$ rank from bottom $- 1$ $= 16 + 27 - 1 = 42$ (Rahul is counted in both ranks, so he is subtracted once).

Therefore, there are $42$ students in the class.