Considering that you know the concept of odd days in calendar
Every 100 years have 5 odd days.
Every 400 years has->((4*5)+(1))%7=0 odd days because 400th year is itself a leap year
so 0-2000 years has 0 odd days.
now 2001-2003 each have 1 odd day and 2004 has 2 odd days because of being a leap year and 26 days of january 2005 you take
((1+1+1)+2+26) mod 7=3
So, the date 26th January 2005 is 3rd odd day and it is a Wednesday.