On 8th Feb, 2005 it was Tuesday. What was the day of the week on 8th Feb, 2004?

The day of the week on 8th Feb, 2004 was Sunday.

Here's the step by step process:

1. We know that 8th Feb, 2005 was a Tuesday.
2. We also know that 2004 was a leap year. This means that February had 29 days.
3. If we go back from 8th Feb, 2005 to 8th Feb, 2004, we are going back 366 days (because 2004 was a leap year).
4. 366 days is 52 weeks and 2 days. The number of weeks doesn't matter because every week has 7 days and therefore repeats the same day of the week.
5. So, we just need to go back 2 days from Tuesday.
6. If we go back 2 days from Tuesday, we land on Sunday.
7. Therefore, 8th Feb, 2004 was a Sunday.