Answer
9,600 drawings
Work Step by Step
1. First draftperson per day:
80 drawings/hour * 8 hours = 640 drawings per day
2. Second draftperson per day:
120 drawings/hour * 8 hours = 960 drawings per day
3. First draftperson after 30 days:
640 drawings * 30 days = 19,200 drawings
4. Second draftperson after 30 days:
960 drawings * 30 days = 28,800 drawings
5. The difference after 30 days:
28,800 drawings - 19,200 drawings = 9,600 drawings