There are 5 school days in a week: 5 days/week x 2 containers of milk/day = 10 containers of milk every week

Finally the number of container for 3 weeks is 3 weeks x 10 containers/week = <<3*10=30>>30 containers

# Answer

30
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Emma buys 2 containers of milk every school day for lunch. She does not go to school on the weekends. How many containers of milk does she buy in 3 weeks?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
30
Emma buys 2 containers of milk every school day for lunch. She does not go to school on the weekends. How many containers of milk does she buy in 3 weeks?
train