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Here is the problem: 15 percent tip on 60.

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The original price is 60 and it increases by 15 percent, so the percent change is 15 percent. Percent increase or decrease; old equals 60, p equals 15 percent; solve for new.

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Read the problem. The original price is 60 and it increases by 15 percent, so the percent change is 15 percent.

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Identify the known values. Percent increase or decrease. Known: old equals 60, p equals 15 percent. Unknown: new value (new).

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Write the equation. new equals old times (1 plus p/100).

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Solve for new. new equals 60 times (1 plus 0.15).

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Result. new equals 69.

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So the answer is Tip equals 9 (total with it equals 69).

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Substitute the known values into new equals old times (1 plus p/100) and isolate new. Keep units consistent (for example miles, miles per hour and hours).

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Substituting new equals 69 back into new equals old times (1 plus p/100) balances both sides, which checks out.