You have to divide both the numerator and the denominator by the same number. Or we could write this as 63 over 1 newspapers per hour.
So if you divide 189 by 3, you get 63, and if you divide 3 by 3, you're going to get 1.
And then they ask us, how much would 7 markers cost?
And let's just set x to be equal to our answer. So the way to solve a problem like this is to set up two ratios and then set them equal to each other. The ratio of 9 markers to the cost of 9 markers is equal to 7 markers to the cost of 7 markers.
And then you would just have to essentially solve for x. And we could do all of the different scenarios like this. So if we have 5 people for 2 eggs, then for 15 people, we are going to need x eggs. So all of these, we've essentially set up the proportions that describe each of these problems.
You could also say the ratio between 7 apples and x apples is going to be the same as the ratio between the cost of 7 apples and the cost of 8 apples. And then you can go later and solve for x to actually get the answer.So this first sentence tells us that she delivers, or she takes, 3 hours to deliver 189 newspapers. So if we were to just flip it, we would have 189 newspapers for every 3 hours, which is really the same information. We're just flipping what's in the numerator and what's in the denominator. So let's divide this numerator and this denominator by 3 to simplify things. If you're behind a web filter, please make sure that the domains *.and *.are unblocked. 24-- when the numerator is 24, the denominator is 40. But then they want us to write equivalent ratios where we have to fill in different blanks over here-- here in the denominator and here in the numerator. And either the numerators are going to be the same, or the denominators are going to be the same. Here, it's just incrementing by 1, but the ratios are not the same. So we're not going to be able to-- this right over here is not a legitimate table. Then when you double the distance, we double the time.We're told this table shows equivalent ratios to 24 to 40. And there's a bunch of ways that we could actually tackle this. If you compare the 3 to the 12, to go from 12 to 3, you have to divide by 4. So in the denominator, you also want to divide by 4. And then we have one more to fill in, this numerator right over here. What we want to do-- because you look at these two things. So let's see if there's any situation here. Well, if you have the same numerator, having a larger denominator will make the number smaller. Each of them runs at a constant speed starting at time 0. So really, the ratio between distance and time should be constant throughout all of these possible tables. If you triple the distance, we're tripling the time. When you triple the distance from 1, you didn't triple the time.So you could say that the ratio of 9 markers to the cost of 9 markers, so the ratio of the number of markers, so 9, to the cost of the 9 markers, to 11.50, this should be equal to the ratio of our new number of markers, 7, to whatever the cost of the 7 markers are, to x. And then you could solve this to figure out how much those 7 markers would cost.And you could flip both sides of this, and it would still be a completely valid ratio. The ratio between the cost of the markers to the number of markers you're buying, 11.50 to 9, is equal to the ratio of the cost of 7 markers to the number of markers, which is obviously 7.If you're seeing this message, it means we're having trouble loading external resources on our website.If you're behind a web filter, please make sure that the domains *.and *.are unblocked. And what I want to do in this video is not solve the word problems but just set up the equation that we could solve to get the answer to the word problems.We do not ask why you are unable or not willing to do it on your own once you contact us with words like “Help me do my homework.” You must have your reasons, and our main concern is that you end up getting a good grade.It does not matter to us, whether you are too busy at work, concentrating on a passion project, or simply tired of a seemingly infinite flow of assignments.