The time it takes to charge the battery of a cell phone is directly proportional to the charge of the battery. The equation, y = 0.21x, is used to approximate the time it takes to charge the battery of a cell phone.
Cell Phone Battery Charge
100
70
60
Bettery Charge (%)
SON
40
BO
20
NON
Time (AM)
Approximate how long it will take the battery to charge to 100%.
4 hours
7 hours
6 hours
5 hours
Please help me