4.7 Percent Applications 1 Percent problems are very common in everyday life; such as grading, taxes, salaries, discounts, and markups. We are still going to solve using either the percent equation, or solve using proportions. Base The base is the whole. It is the original number. Examples: original price, original salary, total number of questions on a test, total number of liters in a solution. Amount Amount is the part, or amount of increase or decrease. It part of the original number. Examples: taxes, raise is salary, missed number of questions on a test. 1. List the variables. Example 1. A factory has an order for custom 600 windows. If 90 windows are complete, what percent of the windows are complete? Solution: 2. Substitute the information into the equation and solve (either method is ok). P  600 = 90 P=? B=600 A = 90 Equation: P  B = A P = 15% 15% of the windows are complete. Answer: 8% were absent. Your Turn Problem #1 12 of 150 workers were absent at L&L Inc. on Monday. What percent of the workers were absent on that day? P = 0.15

4.7 Percent Applications 2 Example 2. Cristina earns $3,250 per month. If she saves 5% for retirement, how much will she save each month? 1. List the variables. Solution: 2. Substitute the information into the equation and solve  3,250 = A P=0.05 B=3,250 A = ? Equation: P  B = A P = 15% 15% of the windows are complete. Answer: The value of the house is $300,000. Your Turn Problem #2 The property tax in Rancho Cucamonga is 1.5% of the value of the house. If a house had a property tax last year of $4500, what is the value of the house? P = 0.15

4.7 Percent Applications 3 1. List the variables. Example 3. A bank tellers hourly wage will increase from $24 to $27.60 What percent increase does this represent? Solution: 2. Substitute the information into the equation and solve. P  24 = 3.6 P=? B=24 A = 3.60 ( =3.60) Equation: P  B = A Answer: 5% decrease Your Turn Problem #3 Gas prices decreased this week from $4 per gallon to $3.80 per gallon. What rate of decrease does this represent? (rate is another word for percent) P = 15% The teller will get a 15% increase. P = 0.15 Percent Increase and Decrease Problems In a percent increase or decrease problem, the amount is the amount of change. The amount is “how much the original number increased or decreased by”. For example: A TV is on sale from $400 to $320. A = 400–320 = 80.

4.7 Percent Applications 4 Example 4. A LCD TV is on sale for 24% off. If the original price was $800, find the sale price. 1. List the variables. Solution:P=24 B=800 A = ? 2. Substitute the information into the equation and solve. A =192 Equation: 0.24  800 = A Sale Price $800 - $192 = $608 The sale price is $608. Your Turn Problem #4 An employee’s salary for Alar Services is $37,500. Next year, she will get an 8% increase in salary? What will her new salary be? $192 is not the price of the TV. It is the amount of decrease. The sale price = original price – amount of decrease Answer: Her new salary will be $40,500. The End B.R