If the 3rd of the month is a Monday, then the 10th will also be a Monday (3+7). The 17th will be a Monday (10+7), and the 24th will be a Monday (17+7). Therefore, the 21st will be a Saturday (24-3), the 22nd a Sunday, the 23rd a Monday, the 24th a Tuesday, and the 25th a Wednesday. The fifth day from the 21st is the 26th, which would be a Thursday. However, the question asks for the fifth day *from* the 21st, which implies counting starts the day after the 21st. So, the 22nd is the 1st day, 23rd the 2nd, 24th the 3rd, 25th the 4th, and 26th the 5th day. If the 3rd is Monday, then the 21st (3rd + 18 days) will be Monday + 18 days. 18 days = 2 weeks and 4 days. So, the 21st will be a Friday (Monday + 4 days). The fifth day *from* the 21st means the 26th. If the 21st is Friday, then the 22nd is Saturday, 23rd is Sunday, 24th is Monday, 25th is Tuesday, and the 26th is Wednesday.