Percentage: expression of a number as a fraction of 100 (ex. 45% = 45 / 100)
Unknown Number: variable (ex. An unknown number is divided by 3 = x / 3)
Times / Of: multiplication (ex. 15% of an unknown number = .15x)
Is: equal to (ex. y is 3 more than an unknown number: y = x + 3)
In terms of: variable remains in answer (ex. “x in terms of y”: 3 + x = y --> x = y - 3)

RULES FOR SAT PERCENT PROBLEMS
1) When a “%” is added to a number, the decimal point is moved two spaces to the right.
    (ex. 0.35 = 35%; 0.08 = 8%; 1.5 = 150%; 4 = 400%; 10 = 1,000%)

2) When a fraction is turned into a decimal, divide it.
    (ex. 3/4 = .75 = 75%; 5/2 = 2.5 = 250%)

3) Percent of Change = (New Quantity - Original Quantity) / Original Quantity × 100%

SAMPLE SAT PRACTICE QUESTIONS FOR PERCENTS

1. A retail store determines the ticket price by increasing the wholesale price by 25%. After a 15% discount off the ticket price, a DVD             player is $68. What is the wholesale price of the DVD player?

      Solution
      A) Ticket price = t; Discount = -15% = -.15t
            t -.15t = 68
            .85t = 68
            t = 80

      B) Wholesale price = w = ?; Increase = 25% = .25w
            w + .25w = t
            1.25w = 80
            w = 64

2. If 60 percent of m is equal to 10 percent of 30 percent of k, what is k in terms of m?

     Solution
    A) 60 percent of m (.6m)
         is equal to (=)
         10 percent of 30 percent of k = (.10)(.30)(k)

    B) .6m = (.10)(.30)(k)
         .6m = .03k
         20m = k

SAT Math: Percent Problems

Lesson Includes:

—SAT Math Terms for Percent Problems

—Rules for Percent Problems

—Sample SAT Practice Questions

—Practice Questions

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PERCENTS REVIEW QUIZ

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