What is Rohan's rank from the top in the class of 30 students?
I. Meera is 4 ranks below Rohan and twenty-first from the bottom.
II. Arjun is two ranks above Rohan and is twenty-seventh from the bottom.

Explanation

From I, it is clear that Rohan has (1 + 3 + 20) = 24 students below him in rank, namely Meera, 20 students below Meera and 3 students between Rohan and Meera. Thus, there are [30- (24 + 1)] = 5 students above Rohan in rank. So Rohan is `6^(th)` from top.
From II, we find that Arjun is `27^(th)` from the bottom i.e. `4^(th)` from the top. Since Arjun is two ranks above Rohan, so Rohan is `6^(th)` from the top.
Thus, either I alone or II alone is sufficient to answer the given quention.