21 is 87 percent of what number? ― JustinTOOLs.com

What is percentage?

In mathematics, a percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%", or the abbreviations "pct.", sometimes the "pc" is also used. For example, 25% is equivalent to the decimal 0.25, or the fraction ²⁵/₁₀₀.

Basic formula for calculating percentages

Although the percentage formula can be written in different forms, it is essentially an algebraic equation involving three values.

P% × V1 = V2

P% is the percentage, V1 is the first value that the percentage will modify, and V2 is the result of the percentage operating on V1. The converter/caculator provided automatically converts the input percentage into a decimal to compute the solution.

[#1] What is 5% of 100?

ANSWER: 5. Calculation: (5/100) x 100 = 5 (or) 0.05 x 100 = 5

[#2] 5 is what percent of 10?

ANSWER: 50%. Calculation: (5x100) / 10 = 50.00% (or) 500 / 10 = 50.00%

[#3] Percent change from 5 to 20?

ANSWER: 300%. Calculation: (20-5)/5 x 100 = 300%

[#4] 5 is 25% of what number?

ANSWER: 20%. Calculation: 5/25% or 5/.25 = 20

21 is 87% of what number?

1. Find the Percentage of a Known Number.

2. Find the Percent of Two Known Numbers.

3. Find the Percent Change, Increase or Decrease between two numbers.

4. Find a Number from a Known Percentage and a Number.