Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Chapter 2 Equations, Inequalities, and Problem Solving

2-2 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Applications with Percent Converting Between Percent Notation and Decimal Notation Solving Percent Problems 2.4

Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Percent Notation n% means

2-4 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example Convert to decimal notation: a) 34% b) 7.6% Solution a) 34% = 34  0.01 = 0.34 b) 7.6% = 7.6  0.01 = 0.076

2-5 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Percent To convert from percent notation to decimal notation, move the decimal point two places to the left and drop the percent symbol.

2-6 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example Convert the percent notation in the following sentence to decimal notation: Marta received a 75% on her first algebra test. Solution Move the decimal point two places to the left.

2-7 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Percent To convert from decimal notation to percent notation, move the decimal point two places to the right and write a percent symbol.

2-8 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example Convert to percent notation: a) 3.24b) 0.2c) Solution a) We first move the decimal point two places to the right: and then write a % symbol: 324%

2-9 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example b) We first move the decimal point two places to the right (recall that 0.2 = 0.20): and then write a % symbol: 20% c) Note that 3/8 = We move the decimal point two places to the right: and then write a % symbol: 37.5%

Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Key Word in Percent Translations “Of” translates to “” or “  ”. “What” translates to a variable. “Is” or “Was” translates to “=”. % translates to

2-11 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example What is 13% of 72? Solution Translate: Thus, 9.36 is 13% of 72. The answer is 9.36.

2-12 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example 9 is 12 percent of what? Solution Translate:

2-13 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example What percent of 60 is 27? Solution Translate: n = 27 ÷ 60

2-14 Copyright © 2014, 2010, and 2006 Pearson Education, Inc. Example To complete her water safety course instruction, Catherine must complete 45 hours of instruction. If she has completed 75% of her requirement, how many hours has Catherine completed? Solution Rewording: What is 75% of 45? Translating: a = 0.75  45 a = Catherine has completed hours of instruction.