Last year there were 1,435 8th graders at a school. this year there are 1,220. what is the percent change in the number of 8th graders

Hello! So to solve this question, we can write and solve a proportion. We write the proportion as change/original = x/100, where change is the distance between two number and the original is the previous number. Percents are parts of 100, so x is a percentage out of 100%. 1,435 - 1,220 is 215. Now, set it up like this.

215/1,435 = x/100

Cross multiply the values to get 21,500 = 1,435x. Divide each side by 1,435 to isolate the "x". 21,500/1,435 is 14.9825783972 or 15 when rounded to the nearest whole number. The percent change in the number of 8th graders is about 15%.

It will be a whole number.