The percent equation has three parts: percent (P), amount (A), and base (B).
"P % of B is A" is the basic form of the percent equation. This can be written algebraically as
The following three examples show how the percent equation can be used to solve basic percent problems:
Example 1 : What is 20% of 18?
Solution: Write this out algebraically.
Convert 20% to decimal form:
20% = 0.2
The basic equation is A = 0.2 x 18
Solve for A:
A = 3.6
20% of 18 is 3.6.
Example 2: What percent of 54 is 9?
Solution: Write this out algebraically.
Let P represent the percent.
The basic equation is 0.01P x 54 = 9
Simplify the left side of the equation:
0.54P = 9
Solve for P:
of 54 is 9.
Example 3: 18 is 25% of what number?
Solution: Write this out algebraically.
Convert 25% to decimal form:
25% = 0.25
The basic equation is 18 = 0.25 x B
Solve for B:
B =
18 is 25% of 72.
0 out of 0 correct.