This model is made with 20 cubes. What percentage of cubes in the model is black?
So we can count the black cubes and there are seven in total. 13 of the cubes are white. The total number of cubes is 20. So we can say that seven out of 20 cubes are black. We have to write this as a percentage. We know that percent means out of 100. The numerator has changed from 20 to 100. And if we multiply 20 by five, that gives us 100.
So we need to multiply the number on top, which we call the numerator, by five as well. Seven out of 20 or seven twentieths is equal to thirty-five hundredths or 35 out of 100. 35 out of 100 is 35 percent.
So 35 percent of cubes in the model are black.