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? Give me reasons, before answering the question
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 = 30 containers. So the final answer is 30.