SOLUTION: The electricity costs of a business decreased from $12,000 one year to 10,920 the next. What is the rate of decrease? I know the difference if $1080.00 from one year to the nex

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Question 47766This question is from textbook Beginning Algebra
: The electricity costs of a business decreased from $12,000 one year to 10,920 the next. What is the rate of decrease?
I know the difference if $1080.00 from one year to the next but how do I get the % of decrease which formula do I use?
Thank You This question is from textbook Beginning Algebra

Answer by tutorcecilia(2152) About Me  (Show Source):
You can put this solution on YOUR website!
Use the formula for percentage increases and decreases:
(Old amount) - (New amount) / (old amount) x 100% = Percent of decrease
.
(12,000) - 10,920)/(12,000) x 100% = Percent of decrease
1080/12,000 x 100%
.09 x 100%
9% = Percent of decrease
.
Check:
12,000 x .09 (9%) = 1080
12,000 - 1080 = 10,920 [Checks out]
.