How much is 40 percent off 28?

Answer 1

For this type of problem, you will want to set up a proportion. You know that 40 as a percentage would be equivalent to 40 over 100. Because you are finding 40 percent of 28, you know that 28 is a denominator, like 100 for 40. But you don't know what the numerator for 28 is. Set up what you know in an equation and you can solve for x:

40 = x

100 28

(Please don't mind the lack of lines for the fractions, as I am not sure how to implement them.) Next, you need to cross multiply, or multiply the denominators to the opposite sides' numerators, resulting with:

1120 = 100x

Now, of course, you need to divide each side by 100.

11.2 = x

So, forty percent of twenty-eight is eleven and a fifth.