Practice: Finding percents. Next lesson. Current timeTotal duration Math: 6. Google Classroom Facebook Twitter. Video transcript is what percent of 80?
These problems tend to kill people because on some level they're kind of simple, they're just and an 80 there, and they're asking what percent. But then people get confused. They say, do I divide the by the 80? The 80 by ? Or is it something else going on? And you really just have to think through what the language is saying. They're saying that this value right here, this , is some percentage of 80, and that some percentage is what we have to figure out. What percent?
So if we multiply 80 by this what percent, we will get So let's view it this way. We have If we multiply it by something, let's call this something x. Let me do that in a different color. If we multiply 80 by something, we are going to get And we need to figure out what we need to multiply 80 by to get And if we just solve this equation as it is, we're going to get a value for x.
And what we need to do is then convert it to a percent. Another way you could have viewed this is is what you get when you multiply what by 80? And then you would have gotten this number, and then you could convert it to a percent. So this is essentially the equation and now we can solve it. If we divide both sides of this equation by 80, so you divide the left-hand side by 80, the right-hand side by 80, you get x.
They both share a common factor of 20, so divided by 20 is 5, and 80 divided by 20 is 4. But they want to know what percent of If they just said is what fraction of 80, we would be done. But they want to say what percent? So we have to convert this to a percent, and the easiest thing to do is to first convert it into a decimal, so let's do that. Let me do it in magenta. So 5 divided by 4. You want to have all the decimals there, so let's put some zeroes out here. Let me switch up the colors.
You subtract. You get 5 minus 4 is 1. Bring down the next zero. And of course, the decimal is sitting right here, so we want to put it right over there. So you bring down the next zero. No remainder. So this is equal to 1. So far, we could say, is 1. This is really just as a number. I guess you could call it a decimal, but it's a whole number and a decimal. It would be a mixed number if we didn't do it as a decimal. So to write it as a percent, you literally just have to multiply this times , or shift the decimal over twice.
And that makes complete sense. But we are done. We've solved the problem. Up Next.