1600 years contain 0 odd day. 300 years contain 1 odd day. 100 years contain 5 odd days. :. 2000 years contain (0 + 1 + 5) odd days = 6 odd days. 1st Jan, 2001 has one odd day. :. Total number of odd days upto 1st Jan, 2001 = 7 odd days = 0 odd days. :. The day will be Sunday