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15 increased by 20% = 18

15 increased by 20 percent is 18. Step-by-step solution with the formula and worked example.

15 increased by 20% = 18
increased by %

Solution: 15 increased by 20 percent

Increase = 20% × 15 = 3
Result = 15 + 3 = 18

Step-by-step explanation

  1. Find the increase: 20% of 15 = 3.
  2. Add it to the original: 15 + 3 = 18.
  3. Shortcut: multiply by (1 + 20/100) = ×1.2.

Good to know

Shortcut: increasing by 20% is the same as multiplying by 1.2 (that is 100% + 20%). So 15 × 1.2 = 18 in a single step — handy for adding tax, interest or a markup.

Frequently asked questions

15 increased by 20 percent
15 increased by 20% = 18.

How is it calculated?
See the step-by-step solution above — it uses the standard percentage formula.

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