Welcome welcome page Zoom Room Zoom logo Jamboard Jamboard logo Textbook textbook cover Lectures YouTube playlist Calculator scientific calculator on Desmos       valid HTML 4.01
Being a Mather Achievements Syllabus Study Skills Library Playgrounds Resources
Shapeshifting Topic Mad  Science Topic Justice Topic Typicality Health Decisions Topic Personal Finance Decisions Topic Business Decisions Topic

Math OER
Turn In Problems
Mad Science Percentages

The greatest reward for a student is not a good grade. It is the willingness of his teacher to listen to him.

- Nikolay Konstantinov

homework turn in box You attempted the ten exercises for this topic. Those problems did not have an answer key. Use this form to ask me how well you did.

Before using this page, you should have your homework completed on paper. (Try being nice to your eyes and posture by printing the problems so you can work with pencil and paper instead of a screen.) This page is only for submitting your homework. To be short and concise it lacks any diagrams, pictures, or tables needed to work the problems.

Answer every question. Then use the button at the bottom of the page to create a code by processing your answers. Copy-and-paste the code into an e-mail.

Keep trying until you get 8 out of 10 or more.


1. What is 25% of 228?

0.57 5.7 57 5,700

2. What is 40% of 750?

30 300 3,000 30,000

3. The price tag (before sales tax) on an item says $100. The sales tax rate is 5%. What is the total price (including tax)?

$5 $105 $500 $2,000

4. During a sale, a dress decreased in price from $90 to $72. What was the percent of decrease?

20% 80% 120% 125%

5. An investment increases in value from $200 to $216. What is the percent increase?

8% 16% 32% 34.56%

6. A pinball machine that normall sells for $3,999 is on sale for $3,150. What is the rate of discount?

$849 21.2% 98.5% 101.6%

7. An investment of $3,000 increases in value by 4%. What is the increase?

$120 $1,200 $3,120 $4,200

8. An investment of $4,000 increases in value by 8%. What is the new value?

$320 $3,200 $4,320 $7,200

9. An investment of $5,000 decreases in value by 2.4%. What is the new value?

$1,200 .024 $3,800 $4,880 $5,120

10. An investment of $6,000 decreases in value by 2%. Then it decreases by another 5%. What is the final value?

$2,400 $5,400 $5,580 $5,586