Official Guide Explanation:
Problem Solving #111




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Solution and Metadata

Question: 111
Page: 167
Difficulty: 5 (Moderate)
Category 1: Arithmetic > Decimals >
Category 2: Arithmetic > Percents > Percent Change
Category 3: Word Problems > Discount >

Explanation: First, this question will be easier without the decimals. It doesn't matter whether we're talking about forty cents or forty dollars or forty whatever - units, so stick with what's easy. The non - reduced price of two candy bars is 80; the sale price is 75. Percent change is equal to ((difference)/(original)), so in this case it's ((80 - 75)/80) = (5/80) = (1/16). It's helpful to know that (1/16) = 0.0625, but if you don't have that fact in your toolbox, it's easy enough to approximate. You can set up a ratio to find the percent: (1/16) = ((x)/100). Since 100 is a little more than 6(16), x is a little more than 6.

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