Here are the steps to track your Speed Post letter:
1. Go to the India Post website: https://www.indiapost.gov.in/.
2. Click on the "Track Consignment" link in the top right corner of the page.
3. Enter the Speed Post tracking number (consignment number) in the "Article Number" field and click on the "Track" button.
4. The website will display the current status of your letter, including its location and expected delivery date.
I hope this information is helpful in determining the delivery time for your letter from Bangalore to Annamalai University.