1. (2020·哈尔滨模拟) Xiaohong has four activities from 8:00 a.m. to 4:00p.m. every Sunday. How long is her lunch hour according to the table?

Piano Class	English	Lunch Hour	Painting Class	Dance Class
2 hours	100 minutes	?	100 minutes	Half an hour
Note: have a rest (twenty minutes) between two classes in the morning and the afternoon