Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Chapter 5 Percents

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. 5.6 Applications of Percent

Martin-Gay, Developmental Mathematics, 2e 33 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Example percent baseamount 18% of 3680 is what number? 18% of Frank’s wages are withheld for income tax. Find the amount withheld from Frank’s wages of $3680 per month. Thus, $ were held from Frank’s wages.

Martin-Gay, Developmental Mathematics, 2e 44 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Example Mr. Buccaran, the principal of Slidell High School, counted 31 freshmen absent during a particular day. If this is 4% of the total number of freshmen, how many freshmen are there at Slidell High School? 31 is 4% of what number? Now we solve for n. 31 = 4% · n 31 = 0.04 · n There are 775 freshmen in the school. Method 1 continued

Martin-Gay, Developmental Mathematics, 2e 55 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. continued Mr. Buccaran, the principal of Slidell High School, counted 31 freshmen absent during a particular day. If this is 4% of the total number of freshmen, how many freshmen are there at Slidell High School? 31 is 4% of what number? There are 775 freshmen in the school. Method 2 amountpercent base

Martin-Gay, Developmental Mathematics, 2e 66 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Finding Percent of Increase Percent of Increase Then write the quotient as a percent.

Martin-Gay, Developmental Mathematics, 2e 77 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Example First we find the amount of increase; 19.9 – 13.1 = 6.8. The average soft-drink size has increased from 13.1 oz to 19.9 oz over the past two decades. Find the percent increase. (Source: University of North Carolina at Chapel Hill, Journal for American Medicine) The amount of increase is 6.8. To find the percent of increase,

Martin-Gay, Developmental Mathematics, 2e 88 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Finding Percent of Decrease Percent of Decrease Then write the quotient as a percent.

Martin-Gay, Developmental Mathematics, 2e 99 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Example First we find the amount of decrease; 3250 – 2100 = The amount of decrease is To find the percent of decrease, John Smith decided to decrease the number of calories in his diet from 3250 to Find the percent decrease.