Use this problem based task to generate a need to graph relationships, analyze linear relations, and extrapolation.

Act 1- Video

When will the phone charge?
1. Give an answer that is too high.
2. Give an answer that is too low.
3. Find how long it will take to charge.

Act 2 – hints
1. Make a table of values comparing the time and the percentage.
2. Graph the relation.
3. Find an equation to model this relation.

Act 3 – Video

1. What could cause the difference in answers?