As per the given above question , we know that
August 15, 1947 = ( 1600 + 300 + 46 ) years + January 1 to August 15th, of 1947
August 15, 1947 = ( 1600 + 300 + 46 ) years + ( 365 - August 16 to December 31 1947 )
1600 + 300 + 46 ) years
August 15, 1947 = ( 1600 + 300 + 46 ) years + ( 365 - 138 ) days
Now , 1600 years give 0 odd day
300 years give 1 odd day
46 years give 1 odd day
Number of odd days = 0 + 1 + 1 (from 11 leap years and 35 ordinary years) + 3 = 5 odd days
Hence , The day was Friday.