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Here is the problem: A number decreased by 15 percent is 68. What is the number?

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Let x be the number: “a number decreased by 15 percent” becomes x times (1 minus 15 over 100).

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Read the problem. Let x be the unknown number. “a number decreased by 15 percent is 68” translates to x times (1 minus 15 over 100) equals 68.

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Solve the linear equation. 0.85x plus 0 equals 68 → x equals (68 minus 0) / 0.85 equals 80.

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So the answer is The number is 80.

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Let x be the number: “a number decreased by 15 percent” becomes x times (1 minus 15 over 100).

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Substitute x equals 80: (80) times (1 minus 15 over 100) equals 68, which checks out.