My question is: 50% of substitute teachers walk out after 1 hour of teaching. 30% of the remainder quit before lunch. If 60 substitute teachers show up at 7 AM, how many will be left after lunch? Your thoughts:
First find the number of substitute teachers left after half quit: 60 teachers / 2 = 30 teachers. Then find how many teachers quit after an hour but before lunch: 30 teachers * 30% = 9 teachers. Then subtract that number from the number of teachers left after one hour to find how many are left after lunch: 30 teachers - 9 teachers = 21 teachers. The final answer: 21.