Answer:
20% of 1100 is 220, so two hundred and twenty students brought their lunch to school on Thursday (and every other school day).
Step-by-step explanation:
The day of the week is a distraction. All you need to know is that 20% of 1100 students bring their lunch to school every day. 20% of 1100 is 200 + 20, or 220. So 220 students bring their lunch to school every day.