Algebra 1 : Percent of Change
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Example Questions
Example Question #81 : How To Find The Percent Of Increase
Find the percent increase form 
For this type of problem we use this formula:
"Difference" is simply the difference between the two numbers given, and "original" is the number that is stated usually after the word "from" , example: from ____ to ____. In this problem our formula will be filled in as follows:
This our percent increase.
Example Question #82 : How To Find The Percent Of Increase
The cost of gasoline last week was 
To find a percentage increase, use the following formula:
By substituting, we get
Example Question #81 : How To Find The Percent Of Increase
Bob took out a personal loan from the bank in the amount of 
To find the percent increase, we want to first divide the total increase by the initial cash amount:
Next we multiply the given value by 
Example Question #84 : How To Find The Percent Of Increase
Henry grows his own produce in a garden. Last week Henry harvested 
To determine the percent increase, we must determine the difference between the 2 values and divide them by the initial yield:
Example Question #81 : How To Find The Percent Of Increase
A certain town has seen a recent increase in population, growing from 
To find the percent of increase, we want to divide the number of new residents by the original population and multiply that decimal value by 
Example Question #86 : How To Find The Percent Of Increase
Sally currently makes $90000 per year as an engineer. After several years working for her engineering firm, Sally's supervisor notices superior quality of Sally's work, and decides to raise her annual salary to $112500. By what percentage did Sally's salary increase?
The general formula for calculating percent change is
In our case, the new (value) is Sally's new salary and the original (value) is her old salary. Plug these values into our equation and simplify.
Example Question #87 : How To Find The Percent Of Increase
Last week, gasoline cost $2.50 a gallon. This week, gasoline costs $2.75 a gallon. Find the percent increase rounded to the nearest percent.
To find percent increase, we use the formula
So, we can substitute our values into the formula. We get
Therefore, the percent increase is
Example Question #81 : How To Find The Percent Of Increase
Last week, you bought cheese for $2 a pound. This week, you bought it for $3.50 a pound. Find the percent increase. Round to the nearest percent.
1.5%
80%
50%
75%
2%
75%
To find the percent of increase, we use the following formula:
The original price is $2. The new price is $3.50. So we can substitute. We get
Therefore, the percent increase is 75%.
Example Question #89 : How To Find The Percent Of Increase
If the field botany course offered by a local university increases its enrollment from 18 students to 27 students, what is the percent increase in the number of students?
If the field botany course offered by a local university increases its enrollment from 18 students to 27 students, what is the percent increase in the number of students?
To find the percent increase, we need to divide the difference by the original number.
So, find the difference:
and divide by the original
Not that it is NOT a 
Example Question #91 : How To Find The Percent Of Increase
If the number of Republican voters in a certain district has decreased from 150,000 to 78,560, what is the percent decrease in the number of Republican voters?
If the number of Republican voters in a certain district has decreased from 150,000 to 78,560, what is the percent decrease in the number of Republican voters?
To find the percent of decrease, we need to divide the difference by the original number:
So the number of Republican voters decreased by about
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