Percent of Increase, Decrease, Discount Topic Index | Algebra Index | Regents Exam Prep Center

There are many situations that involve increasing or decreasing an amount by a certain percent.  Check out the following examples:

 1 You normally work at the mall over the spring break for \$450.  This year the boss tells you that you will be receiving a 7% raise.  How much of an increase will you be receiving?  How much will you be earning in total this year?

r = 7% • 450
r = 0.07 • 450
changing 7% to a decimal
r = 31.5
Your total earnings will be \$450 + \$31.50
which equals \$481.50.

 2 Your dream CD player is on sale for 20% off the original price.  If the original price is \$270, what is the sale price?
 Solution: First, we will find the amount of the discount. The discount = 20% of original price. Let x = the discount. x = 20% • 270 x = 0.20 • 270 x = 54 The discount is \$54. Now, the sale price will be \$270 - \$54 which equals \$216 for the sale price.

 3 The enrollment at a local elementary school had 560 students last year.  This year the enrollment has decreased by 48 students.  What is the percent of decrease to the nearest tenth of a percent?
Solution:

The enrollment decrease =  the percent of decrease of 560.

Let x
= percent of decrease

Answer to nearest tenth of a percent:  8.6%

 Topic Index | Algebra Index | Regents Exam Prep Center Created by Donna Roberts