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20 decreased by 10% = 18

20 decreased by 10 percent is 18. Step-by-step solution with the formula and worked example.

20 decreased by 10% = 18
decreased by %

Solution: 20 decreased by 10 percent

Decrease = 10% × 20 = 2
Result = 20 − 2 = 18

Step-by-step explanation

  1. Find the decrease: 10% of 20 = 2.
  2. Subtract it from the original: 20 − 2 = 18.
  3. Shortcut: multiply by (1 − 10/100) = ×0.9.

Good to know

Shortcut: decreasing by 10% is the same as multiplying by 0.9 (that is 100% − 10%). So 20 × 0.9 = 18 in one step.

Frequently asked questions

20 decreased by 10 percent
20 decreased by 10% = 18.

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

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