Algebra 1 : Percent of Change
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Example Questions
Example Question #13 : How To Find The Percent Of Decrease
Jimmy's magazine kiosk has seen a decline in sales for January. December sales totaled 
To find the percent of decrease, we take the difference in sales and divide that by the original sales income:
Example Question #14 : How To Find The Percent Of Decrease
Oscar brought 72 cookies to a company picnic. By picnic's end there were only 7 cookies left. By what percentage did Oscar's batch of cookies decrease?
To determine the percent of decrease, we must first find the difference between the initial and diminished counts and divide the difference by the initial value:
Next, we multiply the given value by 
Example Question #15 : How To Find The Percent Of Decrease
Charlie bought stock initially valued at 
First we want to get the total cash value of depreciation and divide that by the initial stock value:
To get the percent value of decrease, we then multiply the given decimal by 
Example Question #121 : Percent Of Change
Paul wanted to sell his car last year. At the time, he was fairly certain that his car was worth $15000. 1 year later, Paul has finally gotten around to selling his car. Unfortunately, due to depreciation in value, the car is only worth $12000. By what percent, did Paul’s car decrease in value?
Let 
Plug in the appropriate values into this expression.
Paul's car lost 20% of its value in 1 year.
Example Question #11 : How To Find The Percent Of Decrease
The cost of milk last week was $2.50 a gallon. This week, it is on sale for $2 a gallon. Find the percent of decrease.
To find the percent of decrease, we use the formula
So, we will substitute our values.
We get
Therefore, the percent decrease is 20%.
Example Question #18 : How To Find The Percent Of Decrease
Dr. Beverly Crusher is looking at how many patients she has treated over the last several years. She is interested to see how many patients have had the flu each year. She notices that last year she treated 
To find the percent decrease, we need to find how many less patients she has treated (the decrease). This is just taking the difference between the patients she treated last year and those she treated this year,
Now we can just divide this number by the total patients she treated last year to get a decimal,
To turn it into a percentage you just multiply it by
The formula to get the percent decrease is the decrease divided by the initial total, multiplied by
Example Question #19 : How To Find The Percent Of Decrease
Last week, the price of carrots at the farmer's market was 
To find percent decrease, we use the following formula:
So, if we substitute, we get
If we round to the nearest percent, we get 33%.
Example Question #121 : Percent Of Change
A bag of candy has 200 pieces when opened. After eating some, there are 146 left. What is the percent decrease?
None of the other answers.
Find the amount of decrease, divide it by the starting number, and multiply by 100 to convert to a percentage.
A 27% decrease.
Example Question #2911 : Algebra 1
Kerri wanted to make a chart to calculate how much time she was spending on studying for her tests. For her midterm, she charted that she spent 1 hour and 30 minutes studying every day for three days. Since she was grasping the material, for the final exam Kerri only studied 3 hours total. What is the percent change for the amount of time studying between the midterm and final exam?
The first task to do in this problem is to convert the time amounts for studying to either minutes or hours. The problem says Kerri spent three days of studying for 1 hour and 30 minutes each, which is also 1.5 (30 minutes is half an hour) hours. Multiply 3 days by 1.5 hours o get 4.5 hours of total studying for her midterm. Since the final exam is already in the unit of hours the amount of 3 hours is ready to be worked with.
Use the percent change formula new amount subtracted by old amount then divided by the old amount and multiplied by 100 to find the percent change.
Kerri studied 33.33% less for the final exam than she did for the midterm.
Example Question #122 : Percent Of Change
You decide that 15 pairs of shoes is far too many and sell 8 of them. Your percent decrease in shoes is?
None of these.
Subtract the new value from the old value:
Divide by the original number:
Multiply by 100:
A 47% decrease in shoes.
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