Answer:
B = 32.5 - 2.5t
Explanation:
Let the initial percentage to be 30%
If it started to loose 2.5% every hour where;
t represents the time after Charlotte left her house
The amount of percent remaining every hour will form an arithmetic sequence as shown;
30, (30-2.5), (30-5.0),...
30, 27.5, 25.0...
Using the nth term for calculating an arithmetic sequence
B = a + (t-1)d
a is the first term = 30
d is the common difference = 27.5-30 = 25-27.5 = -2.5
t is the time
Substitute the given values into the formula;
B = 30 + (t-1)(-2.5)
B = 30+(-2.5t+2.5)
B = 30-2.5t+2.5
B = 32.5 - 2.5t
Hence equation for B, in terms of t, representing the charge remaining in Charlotte's battery, as a percentage, t hours after Charlotte left her house is B = 32.5 - 2.5t