Answer: Part 1: Dan, Part 2: 55%
Explanation:
1. By noon, Jon has painted 1/5 (or 20%) of the hallway and Dan has painted 25% of the hallway. Therefore, Dan has painted more of the hallway than Jon.
2. In total, the two have painted 45% (20% + 25% = 45%) of the hallway by lunchtime. Therefore, 55% (100% - 45% = 55%) needs to be painted after lunch.