When his tablet battery is charged at 75%, Charlie’s tablet battery can last for 15 hours. How many hours will the tablet’s battery charge last when it is fully charged at 100%?
5
20
25
60
If Charlie's tablet battery can last for 15 hours when charged at 75%, it means that each 1% of battery charge lasts for 15/75 = 0.2 hours.
Therefore, when the tablet's battery is fully charged at 100%, it will last for 0.2 * 100 = 20 hours.
So the answer is 20.