Question

when justin left his house this morning, his cell phone was 50% charged and it then started to lose 5% charge for each hour thereafter. write an equation for b, in terms of t, representing the charge remaining in justins battery, as a percentage, t hours after justin left his house.

number of hours since justin left his house	percentage charge remaining on phone battery

|0|
|1|
|2|
|3|

answer attempt 1 out of 2

you must answer all questions above in order to submit.

Explanation:

Step1: Identify initial charge

The initial charge when $t = 0$ is $50\%$, so when $t=0$, $B = 50$.

Step2: Determine rate of change

The battery loses $5\%$ charge per hour. So the charge $B$ decreases by $5t$ (where $t$ is the number of hours) from the initial $50\%$.
The equation for the charge remaining $B$ in terms of $t$ is $B=50 - 5t$.
Now fill in the table:
When $t = 0$, $B=50 - 5\times0=50$.
When $t = 1$, $B=50 - 5\times1 = 45$.
When $t = 2$, $B=50 - 5\times2=40$.
When $t = 3$, $B=50 - 5\times3 = 35$.

Number of Hours Since Justin Left His House	Percentage Charge Remaining on Phone Battery
1	45
2	40
3	35

Answer:

$B = 50-5t$