There are many different ways that one would be able to solve this problem. I am going to show you the percent proportion, which is a/b = p/100, where p is the percentage, and a is a portion of the total number b. So, if we substitute our known numbers into the equation, we get:
20.40/b = 8/100
To simplify this equation, we are going to use cross products, or the multiplication of the numerator of one fraction times the denominator of the other fraction, and setting these two products equal to one another. If done correctly, you should get the simplified equation:
(100)(20.40) = (8)(b)
When we multiply the left and right sides of the equation, we get
2040=8b
Now, we must divide both sides of the coefficient, 8, to get our final answer.
b = 255
Therefore, if Selena earns 8% commission on sales, and her commission was $20.40, then the amount of her sale was $255.00.
