After Cammy gets out of bed in the morning, she completes several activities to get ready for school. The list below shows the numbers of minutes she needs to complete each of these activities.
30 minutes: brush teeth, shower, get dressed
10 minutes: eat breakfast
30 minutes: car ride to school
Cammy must be at school by 8:00 AM. What is the latest time Cammy can get out of bed, complete all her activities, and still get to school on time? Explain why your answer is correct?