If you can in any way contribute, please do.
The above problem appeared in the JEE- Advanced 2015 examination in the second paper. The answer provided in the official answer key is \(9\). However, the problem is widely believed to be incorrect. The authorities conducting the examination accept suggestions related to the correctness of the published key till 11- Jun 2015, 12 noon (Indian standard time). I want to send them a fax related to the error in this problem and to do so, it would really help if the community could offer valuable suggestions about the problem.
Here is an (incorrect) solution which yields the supposed answer: