Percent problems may be solved using several different methods. One method uses multiplication by a constant factor. Work through the examples below to examine the constant factor method as well as a few other methods.
Try the following two examples.
Example 1:
Freddie is downloading a program that is 1.5 megabytes. According to the progress bar, it has finished 30% of the download. How many megabytes have been downloaded so far?
On a separate piece of paper, draw a percent bar that represents how you would use a percent bar to find the amount of data that has been downloaded so far.
What does the problem give you?
What does the problem ask for?
Interactive popup. Assistance may be required.
The problem asks for the number of megabytes that have been downloaded so far.
Try solving the problem using a proportion.
Copy the following table into your notes and fill in the missing information:
Percent |
megabytes |
|
Part |
m |
|
Whole |
100 |
Use the chart to set up a proportion relating the percent to the number of megabytes:
Use this proportion to find m, the number of megabytes downloaded so far.
Finally, let's try the same problem by using an equation.
What is your plan to solve the equation?
Write your plan as an equation.
How many megabytes have been downloaded?
Example 2:
You want to buy a television in an electronics store that offers a payment plan so that you can make payments every month instead of paying all at once. To qualify for the payment plan, the store requires you to make a 20% payment today.
If the television originally cost $1100, how much do you need to pay today?
Use each of the methods described below to solve this problem then click to check your answer.
Create a data table and use it to write a proportion relating the percent to the price you need to pay today.
Write and solve an equation that you could use to solve for the p, the payment you need today if the television has an original cost of c dollars.
When solving equations in the form of y = kx, multiplying by a percent will help you find a part of the larger whole.