Lesson 42 Solving percent problems percent A percent

Lesson 42 Solving percent problems

percent • A percent is a ratio that compares a number to 100. • For example, 50% is 50/100 • There are 3 components that form a percent statement: • 1) the whole is the total amount • 2) the percent is a rate that quantifies an amount measured with respect to the whole • 3) the percentage is a number that represents a percent of a whole

• 25% of 20 is 5 percentage whole • If 2 of the components are known, then the 3 rd can be determined

What number is 25% of 50 • "Is" means = • "Of" means multiply • N= 25% x 50 • N =. 25 X 50 • N = 12. 5

What number is 125% of 64? • n = 125% x 64 • n = 1. 25 x 64 • n = 80

What number is 75% of 200? • n = 75% x 200 • n =. 75 x 200 • n = 150

Using a proportion • A percent statement can also be set up as a proportion • • part (is) = percent • whole (of) 100

What number is 125% of 48? • Set up a proportion. • • • c = 125 48 100 c = 48(125) 100 c = 6000 100 c = 60

Solve by proportion • 15 is what percent of 45? • • 15 = p 45 100 45 p = 15(100) 45 p = 1500 45 45 P = 33 1/3 %

solve • What number is 120% of 25? • 12 is what percent of 72?

Lesson 47 • Solving problems involving the percent of change

Percent of change • The percent of change is the ratio of the amount of change in a quantity to the original amount, expressed as a percent. • The percent of change can be a percent of increase or percent of decrease.

Finding percent of increase or decrease • Number of hats sold in 1999= 14, 260 • Number of hats sold in 2007= 25, 491 • • • Find the percent of change: 25, 491 -14, 260= 11, 231 Amount of increase = 11, 231 =. 79 Original amount 14, 260 79% increase

Percent of increase or decrease? • A music store marks up the price of CD's they purchased at $9. 00 each by 70%. What is the markup and the new price of the CD? • 1) find 70% of the original cost • . 70 x 9. 00=$6. 30 markup • 2) add markup to original price • 9. 00 + 6. 30 = $15. 30 selling price

Percent increase or decrease? • A bookstore is having a sale of 40% off all items. What is the discount and new price of a book that originally cost $12. • 1) find 40% of original cost • . 40 x 12 = $4. 80 discount • 2) subtract discount from original price • 12. 00 - 4. 80= $7. 20 discounted price

practice • A computer store marks up the price for laptops they purchased at $450. each by 65%. What is the markup and new price of each laptop? • A shoe store s having a sale of 25% off all items. What is the discount and new price of a pair of shoes that originally cost $68?