Answer:
B = -0.08t
Explanation:
At 0 hours, the battery of the phone is at 80%. If it decreases by 8% every hour, then that would mean that one hour outside of her house would make her phone's battery 72% (since 80 - 8 = 72). You have to subtract 80 by 8t, with t being how many hours. This would mean that two hours would be 80 - 8(2) = 80 - 16 = 64, and so on. I hope this response helped!