Concept:
In ranking problems, to determine if someone is topper (rank 1), we need clear positional information.
Step 1: Analyze Statement I alone.
15 students are between Hari and Chinu.
This only gives relative distance, not exact ranks.
Statement I alone is NOT sufficient.
Step 2: Analyze Statement II alone.
Chinu is last.
No information about Hari’s position.
Statement II alone is NOT sufficient.
Step 3: Combine both statements.
Chinu is last.
15 students are between Hari and Chinu.
Still, total number of students is unknown, so Hari’s exact position cannot be determined.
Hence, even both statements together are NOT sufficient.