AAA000 Course Title

Introduction: Connecting Your Learning

woman using laptop computerPercents are a part of everyday life. Consider the following examples:

— 32.76% of Web users use Google Chrome as their primary Web browser (Google Chrome).

— 15% of Web searches on Google every day have never been seen before (Facts about Google and Competition).

— In Fall 2008, an estimated 100% of public schools had one or more instructional computers with Internet access (Educational Technology in U.S. Public Schools).

The goal of this lesson is to demonstrate how they are incorporated into real-world settings and how to calculate solutions instead of creating more problems.

Focusing Your Learning

Lesson Objectives

By the end of this lesson, you should be able to:

  1. Identify various uses of percent.
  2. Set up and solve equations pertaining to sales tax, commission, discounts, and mark ups.

Key Terms


Application Problems using Proportions and Percents

Review the following real-life application problems to see how you take the information from a basic word problem and create an equation. The examples provided illustrate how to solve the problem.

Percent of Increase



One year a spool of wire sold for $845. The manufacturer decides to raise the price of the following year's product by 6%. How much did the spool of wire increase in price, and what is the new price of the wire?


Increase: The amount of increase is calculated by 0.06 x $845, which is $50.70.

Total price: The total price can be calculated two ways:

  1. $845.00 + $50.70, which is $895.70


  2. 1.06 x $845.00, which is $895.70
  3. (The price is being raised, so 1.06 represents the original cost, 100%, plus the additional cost, 6%.)


Percent of Decrease



A manufacturer creates a computer with 240 gigabytes of storage on the hard drive. After loading some start-up software and advertisements, the computer lost 22% of its hard drive storage capacity. How much space did the start-up software use, and how much storage space is left on the computer? Answers should be in gigabytes.


Decrease: The amount of decrease is calculated by 0.22 x 240, which is 52.8 gigabytes.

Total Storage Space Remaining: This total can be calculated two ways:

  1. 240 – 52.8, which is 187.2 gigabytes


  2. 0.78 x 240, which is 187.2 gigabytes
  3. (This means 78% of the hard drive storage capacity remains when 22% is taken away from the original 100%.)


Sales Tax

Sales tax = Sales tax rate x Purchase price

Total price = Purchase price + Sales tax


Total price = (1 + Sales tax) x Purchase price



Justin is in search of a new GPS navigator for his car. At one of the electronic stores, he notices a GPS Navigator with a 4.3-inch screen and speech recognition for only $799. If the sales tax in his state is 9.1%, what would his total bill be?


Sales tax: The amount of sales tax is calculated by 0.091 x $799 = $72.71.

Total Price: This total can be calculated two ways:

  1. $799 + $72.71 = $871.71


  2. 1.091 x $799 = $871.71


During Justin's search for a new GPS navigator for his car, he finds a big box warehouse store in a neighboring city selling the same GPS navigator with a 4.3-inch screen and speech recognition for $799 plus $65.73 sales tax. Calculate the sales tax rate for this GPS navigator.

Rephrase: The sales tax  is  what percent of the purchase price?
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Translation: $55.93 = n x $799

Sales tax: n = 0.07 then multiply by 100 to convert into a percentage, 7%



Commission = Commission rate x Sales



A local software company has hired you to sell their new product. The hourly rate is well below minimum wage, but the company offers you 3% commission on all sales. You decide to take the job, and in the first week you sell $9,100 worth of software. What is your commission?


Commission: The amount of commission is calculated by 0.03 x $9,100 = $273.



During the month of March, Avery earns $1,032 in commission from $25,170.73 in sales. What is his commission rate?

Rephrase: Commission  is  what percent of the total sales?
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Translation: $1,032 = n x $25,170.73

Commission Rate: n = 0.041 then multiply by 100 to convert into a percentage, 4.1%


Practice Ico

Now you get a chance to work out some problems. You will need to take out a sheet of paper and a pencil to complete the practice problems. You may use a calculator if you would like. Study each of these problems carefully; you will see similar problems on the lesson knowledge check.

Select the link below to work on the practice problems on your own then select the link to the solutions to see how well you did.

Application Problems Proportions and Percents Practice Problems

Solutions: Application Problems Proportions and Percents Practice Problems

Summarizing Your Learning

Throughout this module you have seen how to convert between percentages, decimals, and fractions. You have also learned how word problems can be translated into equations. Most importantly you have seen how percents play a vital role in everyday life: from calculating commission to figuring out the amount of space left on a hard drive.

Now that you have completed this lesson, conduct additional research into how these topics pertain to your particular area of study within the IT world. The two best ways to do this research are to Google the topic or to talk with someone who currently works in that field. Don't limit yourself to only one way of investigation.

Assessing Your Learning

Assignement Ico

Now that you have read over the lesson carefully and attempted the practice exercises, it is time for a knowledge check. Please note that this is a graded part of this lesson so be sure you have prepared yourself before starting.

  1. Complete the Percents: Application Problems Proportions and Percents Knowledge Check.


Ellis, W., & Burzynski, D. (2010, August 18). Ratios and Rates: Applications of Percents.
Retrieved from:


Additional Attributions

Have You Met The Objectives For This Lesson?