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Simple Operations with Percent

Problems with percentages involve three parts: the percent, the total (base) number, and the part of that base number. This section explains how to work with these parts to solve simple operations with percent.

Solving Simple Operations with Percent

Solving Simple Percent Word Problems Transcript

Examples & Activity

Examples

Click on the titles below to view each example.

What number is 35 percent of 90?

Line 1: Translate the words into algebra. Let n equal the number we are trying to find, is represents the equals sign, 35 percent is 0 decimal 3 5, and of means multiply by 90. Therefore, the equation is n equals 0 decimal 3 5 times 90.

Line 2: Multiply 0 decimal 35 by 90 to solve for n, so the n equals 31 decimal 5.

Line 3: Therefore, 31 decimal 5 is 3 percent of 90.

36 is 75 percent of what number?

Line 1: Translate the words into algebra. Let b equal the number we are trying to find. Is represents the equals sign, 75 percent is 0 decimal 7 5, of means multiply by the number, b. Therefore, the equation is 36 equals 0 decimal 7 5 times b.

Line 2: Divide both sides of the equation to solve for b, so the equation is 36 divided by 0 decimal 7 5 equals 0 decimal 75 b divided by 0 decimal 7 5.

Line 3: Simplify to get 48 equals b.

Line 3: Therefore, 36 is 75 percent of 48.

What percent of 36 is 9?

Line 1: Translate the words into algebra. Let p equal the percent, of means multiply by 36, and is represents the equals sign. Therefore, the equation is p times 36 equals 9.

Line 2: Divide both sides by 36 to solve for p, so the equation is 36p divided by 36 equals 9 divided by 36.

Line 3: Simplify so that p equals 1 over 4.

Line 4: Convert the fraction to a decimal by dividing the numerator by the denominator so p equals 0 decimal 2 5.

Line 5: Convert the decimal to a percent by multiplying by 100 percent so p equals 25 percent.

Line 6: Therefore, 9 is 25 percent of 36.

Activity

Try this activity to test your skills. If you have trouble, check out the information in the module for help.

Summary and Worksheet

Attribution

Examples Source: "Prealgebra - opens in a new window" by Lynn Marecek & Mary Anne Anthony-Smith is licensed under CC BY 4.0 - opens in a new window / A derivative from the original work - opens in a new window