Finding a Percent versus Finding an Amount

[One speaker] 

[Video opens to a circle cut into 24 equal slices each having a different color on the left side of the video and on the right side is a drawing of a shirt with a price tag for $20 sitting in a window and a sign, “25% off.” The speaker uses the canvas to write down the concepts she explains.]

Narrator: Welcome to the video on the difference between finding a percent, and finding an amount, based on percent. In the video on finding percentages, we’ve learned that in order to find a percentage, we took the amount, and divide it by the total. In the video on finding the percent of something, we used the percent as a decimal, and we multiplied it by the total, or the original amount. In this first case, we were actually solving for a percent, so we solved for the percent. In the second case, we were solving for an amount.

[Scrolls down to a blank area of the canvas.]

Let’s do an example of each. What percent of an hour is forty-five minutes? So in this case, the amount that we have is forty-five, we have forty-five. So we’re trying to find the percent out of an hour. An hour total, in total minutes is sixty, because there are sixty minutes in an hour. [writes “45÷60 = %”] So if we have forty-five, what percent of an hour is that? Well, forty-five divided by sixty, if we use a calculator, we’d find that this is point seven five, or in percent terms, it equals seventy-five percent. [writes “.75 = 75%”] So that would be our answer, forty-five minutes is seventy-five percent of an hour. So now let’s go the other direction. In this case, how long in minutes is seventy-five percent of an hour? In this case we’re solving for an amount, we’ve been given a percentage. So we have the percentage, and we need to multiply by the total to get the amount. So we have seventy-five percent, which is point seven five, and we’re working in minutes, so our total is sixty, because there are sixty minutes in an hour. So our percent times our total will equal the amount that we’re looking for. [writes “.75 x 60 = amount”] In this case, point seven five times sixty is forty-five. So forty-five minutes are seventy-five percent of an hour.

So just to go over this one more time, when you’re solving for a percent, you take the amount and you divide by the total. Instead, when you’re solving for an amount, you take the percentage as a decimal, and multiply by the total. It all depends on what you’re trying to find, so that’s the important thing. Figure out what you’re trying to find, whether it’s a percent or an amount, and then use the appropriate method.

[End of Video.]