New SAT Math Workbook

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Unformatted text preview: 4 .6 .8 .125 .375 .625 .875 12 % www.petersons.com Percent 73 Exercise 1 Work out each problem. Circle the letter that appears before your answer. 1. 3 1 % may be written as a decimal as 2 5 as an equivalent percent. 12 4. Write (A) (B) (C) (D) (E) (A) (B) (C) (D) (E) 2. 3.5 .35 .035 .0035 3.05 13 20 17 20 17 10 19 20 17 2 41% 41.6% 41 2 % 3 4.1% .41 % 1 % as a decimal. 2 Write as a fraction in simplest form: 85%. (A) (B) (C) (D) (E) 5. 2 3 Write (A) (B) (C) (D) (E) .5 .005 5.0 50.0 .05 3. Write 4.6 as a percent. (A) 4.6% (B) .46% (C) .046% (D) 46% (E) 460% www.petersons.com 74 Chapter 5 2. FINDING A PERCENT OF A NUMBER Most percentage problems can be solved by using the proportion % part = . 100 whole Although this method will work, it often yields unnecessarily large numbers that make for difficult computation. As we look at different types of percent problems, we will compare methods of solution. In finding a percent of a number, it is usually easier to change the percent to an equivalent decimal or fraction and multiply by the given number. Example: Find 32% of 84. Proportion Method 32 x = 100 84 100 x = 2688 x = 26.88 Decimal Method Change 32% to .32 and multiply. 84 × .32 168 252 26.88 Example: Find 12 1 % of 112. 2 Proportion Method 1 2= x 100 112 100 x = 1400 x = 14 12 Decimal Method 112 × .125 560 2 24 11 2 14.000 Fraction Method 1 1 Change 12 % to 2 8 14 1 ⋅ 112 = 14 8 Which method do you think is the easiest? When the fractional equivalent of the required percent is among those given in the previous chart, the fraction method is by far the least time-consuming. It really pays to memorize those fractional equivalents. www.petersons.com Percent 75 Exercise 2 Work out each problem. Circle the letter that appears before your answer. 1. What is 40% of 40? (A) .16 (B) 1.6 (C) 16 (D) 160 (E) 1600 What is 42% of 67? (A) 2814 (B) 281.4 (C) 2.814 (D) .2814 (E) 28.14 2 Find 16 % of 120. 3 4. What is % of 40? 5 (A) 8 (B) .8 (C) .08 (D) .008 (E) .0008 Find r% of s. (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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