Question 476021
Already solved...the day that occurs 2^n days after a Monday will be a Monday only if 2^n is a multiple of 7 (which is impossible). The residues of 2^n modulo 7 are 1, 2, 4 (8 is 1 mod 7, so the pattern repeats), so the only possible days are Tuesday (1 day after Monday), Wednesday (2 days after Monday) and Friday (4 days after Monday).