standard_description: Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output. (Function notation is not required in Grade 8.)
problem_activity: Task
Jerry forgot to plug in his laptop before he went to bed. He wants to take the laptop to his friend's house with a full battery. The pictures below show screenshots of the battery charge indicator after he plugs in the computer.
[IMG]
When can Jerry expect that his laptop battery is fully charged?
At 9:27 AM Jerry makes a quick calculation:
The battery seems to be charging at a rate of 1 percentage point per minute. So the battery should be fully charged at 10:11 AM.
Explain Jerry's calculation.  Is his estimate most likely an under- or over-estimate? How does it compare to your prediction?
Compare the average rate of change of the battery charging function on the first given time interval and on the last given time interval. What does this tell you about how the battery is charging?
How long would it take for the battery to charge if it started out completely empty?


aligns: no