Algebra 1 : How to find the percent of increase

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #11 : Percent Of Change

Angela received an 80 out of 100 on her first geology exam.  On her second exam she scored 86 out of 100.  What was the percentage of increase of her grade from the first exam to her second exam?

Possible Answers:

Correct answer:

Explanation:

Reference number is the total points available

Relative difference is the second exam score minus the first

Example Question #11 : How To Find The Percent Of Increase

Next month, Ned's monthly salary will be increased from $2,400 per month to $3,000 per month. By what percentage did Ned's salary increase?

Possible Answers:

%

%

%

%

None of the other answers

Correct answer:

%

Explanation:

To find the percentage of increase, you must divide the change in amount by the original amount. In this case, the change in amount or amount increased is $600 ($3,000 minus $2,400). The original amount is Ned's original salary, or $2,400. Thus, to find the percentage of increase of Ned's salary, you simply divide $600 by $2400: , which equals to 0.25 or 25%.

Example Question #11 : How To Find The Percent Of Increase

A company reports sales earnings of $85,000 for one year. The next year, the sales earnings are $91,000. By what percentage did the sales earnings increase? 

Possible Answers:

Correct answer:

Explanation:

To find the percentage increase, first find the difference in sales earnings.

Then, divide this by the sales earnings from the first year.

Finally, multiply this fraction by 100 to get the percentage increase.

Example Question #11 : Percent Of Change

Last year, the enrollment of freshmen at a college was 1436. This year, the enrollment increased at a percentage of 22%. What is the number of college freshmen this year?

Possible Answers:

none of these

Correct answer:

Explanation:

First, find the increase in the number of freshmen from last year to this year. Given that the percentage increase is 22%  (0.22 in decimal form), you can find this increased number by multiplying the percentage by 1436

So the number of freshmen has increased by 316. Add this to the number of freshmen last year.

So the number of freshmen for this year is 1752.

Example Question #11 : How To Find The Percent Of Increase

Find the percent decrease from 75 from 50.

Possible Answers:

50%

-50%

25%

100%

Correct answer:

50%

Explanation:

To find the percent change in two numbers, we can use the formula .  In our case, our final value is 75, and our initial value is 50.  Substituting our values into the equation, we get .

Example Question #2802 : Algebra 1

The average temperature in a certain city in May is 64 degrees. On one unusually hot day, the temperature was 88 degrees. What was the percent of increase on the 88-degree day from the original 64-degree average?

Possible Answers:

37.5%

42.0%

24.0%

0.375%

27.3%

Correct answer:

37.5%

Explanation:

For this question, the only difficult part is knowing what is meant by "percent of increase." With questions of this type, we need to know what part of the original whole was added to yield the new, increased value. Here, the original value was 64 and the increased value is 88. First, we find the difference between the two: 

This is the amount of increase. Next, we take , which is our percent of increase in fraction form. The simplified value of this number is , or .

The original number increased by 37.5%.

Example Question #2801 : Algebra 1

Last week, Bob earned 115 dollars.  This week, Bob earned 245 dollars.  What is Bob's percent of increase in earnings between last week and this week?

Possible Answers:

Correct answer:

Explanation:

To find the percent increase of two numbers, use the following formula: 

where  is the new number and  is the original number.  For this problem, our formula would look like this:

 

or

Example Question #16 : Percent Of Change

Megan went to her local grocery store, expecting milk to be its usual price of $2.52 per gallon. To her dismay, she saw that the price had been increased to $2.82. What percent increase was this from the original sale price?

Possible Answers:

 

 

Correct answer:

Explanation:

Basic subtraction shows us that the price of milk increased by $0.30. Now, all we need to do is find what percent $0.30 is of the original price, $2.52. We can do this through cross-multiplication.

If we set , then  will represent the percentage increase and therefore the final answer.

Cross-multiplying yields , which gives .

Divide both sides by 2.52 to isolate x: 

x = 11.9, which is closest to 12%.

Example Question #17 : Percent Of Change

Lucy has  and her mom gives her  allowance, making her total money . What is the percent increase of Lucy's money?

Possible Answers:

Correct answer:

Explanation:

Lucy had $100 and then earned $10. Since her amount of money went up by $10, and 10 is 10% of 100, then her percent increase is 10%.

Also we can use the formula,

Example Question #2811 : Algebra 1

What is the percent increase from  to

Possible Answers:

Correct answer:

Explanation:

In this problem we are asked to find the percent increase from  to  In other words, out of the original number , what percentage of that number was added?

To solve this problem, we first must find the difference from  to , which is  

Now, to find the percent change we simply 

, in this case .

The percent of increase from  to  is 

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