Final answer:
The percent change in the water bill from August ($48.00) to September ($36.00) is a decrease of 25%. To find this, we calculated the change in the bill ($12.00), divided it by the August bill, and then multiplied by 100 to get the percent change.
Step-by-step explanation:
To calculate the percent change in the water bill from August to September, you use the following formula:
Percentage change = [(change in amount)/(original amount)] × 100
So, first we determine the change in the water bill amount by subtracting the September bill from the August bill:
$48.00 (August) - $36.00 (September) = $12.00
Now, we divide this change by the original amount (the August bill):
$12.00 / $48.00 = 0.25
Finally, we convert this number to a percentage by multiplying by 100:
0.25 × 100 = 25%
Therefore, the water bill decreased by 25% from August to September. Since the question asks for the percent change and not the decrease specifically, the correct answer is -25, which represents a decrease.