Math percentage problems can often be confusing since they can have many variations. Whether you need to find the percentage of a number or what percentage a number is of another, each type of problem fortunately follows a set formula to make it simpler. The problem of finding what number that 20 percent of is 8 can be solved with the formula a = p * x, where a is the comparative number, or number after the percent has been applied, p is the percentage amount and x is the original number.
Divide 20 percent by 100 to obtain its decimal form. Dividing 20 percent by 100 equals 0.2.
Set up an equation as 0.2x = 8, which means 20 percent of x equals 8.
Solve the equation by dividing each side by 0.2. Dividing 0.2 from each side results in x = 40. Eight is 20 percent of 40.
About the Author
Chance E. Gartneer began writing professionally in 2008 working in conjunction with FEMA. He has the unofficial record for the most undergraduate hours at the University of Texas at Austin. When not working on his children's book masterpiece, he writes educational pieces focusing on early mathematics and ESL topics.