New SAT Math Workbook

# New SAT Math Workbook

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Unformatted text preview: = ⋅ 100 = 2% 1500 150 50 Example: 12 is what percent of 72? Proportion Method x 12 = 100 72 72 x = 1200 Fraction Method 12 1 2 = = 16 % 72 6 3 2 %. If you have memorized the fractional equivalents 3 Time consuming long division is needed to find x = 16 of common percents, this method requires only a few seconds. Example: What percent of 72 is 16? Proportion Method x 16 = 100 72 72 x = 1600 2 x = 22 % 9 Fraction Method 16 2 200 2 = ⋅ 100 = = 22 % 72 9 9 9 www.petersons.com Percent 79 Exercise 4 Work out each problem. Circle the letter that appears before your answer. 1. 4 is what percent of 80? (A) 20 (B) 2 (C) 5 (D) .5 (E) 40 1 1 of 6 is what percent of of 60? 2 4 4. What percent of 48 is 48? (A) 1 (B) 10 (C) 100 (D) 48 (E) 0 What percent of y is x? (A) (B) (C) (D) (E) x y x 100 y xy 100 100 x y 100 y x 2. 5. (A) (B) (C) (D) (E) 3. 5 20 10 25 15 What percent of 96 is 12? (A) (B) (C) (D) (E) 16 8 1 3 1 2 2 3 37 8 12 1 2 www.petersons.com 80 Chapter 5 5. PERCENTS GREATER THAN 100 When the percentage involved in a problem is greater than 100, the same methods apply. Remember that 100% = 1 1; 200% = 2; 300% = 3 and so forth. Therefore 150% will be equal to 100% + 50% or 1 . Let us look at one 2 example of each previously discussed problem, using percents greater than 100. Example: Find 175% of 60 Proportion Method Decimal Method 60 175 x = 100 60 100 x = 10500 x = 105 Fraction Method × 1.75 300 4200 6000 105.00 3 1 ⋅ 60 4 15 7 ⋅ 60 = 105 4 Example: 80 is 125% of what number? Proportion Method 125 80 = 100 x 125 x = 8000 x = 64 Decimal Method 80 = 1.25 x 8000 = 125 x x = 64 Fraction Method 1 80 = 1 x 4 5 80 = x 4 320 = 5 x x = 64 Example: 40 is what percent of 30? Proportion Method x 40 = 100 30 30 x = 4000 1 x = 133 % 3 Fraction Method 40 4 1 1 = = 1 = 133 % 30 3 3 3 www.petersons.com Percent 81 Exercise 5 Work out each problem. Circle the letter that appears before your answer. 1. 36 is 150% of what number? (A) 24 (B) 54 (C) 26 (D) 12 (E) 48 What is 300% of 6? (A)...
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## This note was uploaded on 08/15/2010 for the course MATH a4d4 taught by Professor Colon during the Spring '10 term at Embry-Riddle FL/AZ.

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