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Part:whole ratios

Sal uses part:whole ratios to compare one type of fruit to a group of fruit.   Created by Sal Khan.

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  • starky sapling style avatar for user lilypuerto21
    In a problem before, we had 32 1/2 times 2. Supposedly, the answer was 65, I'm a little bit confuse why that is the answer, shouldnt we convert the mixed # into a improper fraction and then multiply by 2?

    (21 votes)
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  • male robot hal style avatar for user Aztik
    At a soccer tournament 12 teams are wearing red shirts, 6 teams are wearing blue shirts, 4 teams are wearing orange shirts, and 2 teams are wearing white shirts.

    For every 2 teams at the tournament, there is 1 team wearing _______ shirts.
    Choose 1 answer:

    (Choice A)

    (Choice B)

    (Choice C)

    (Choice D)
    (14 votes)
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  • blobby green style avatar for user Uzair  Tausif
    i am stuck on ratio can you help?
    (9 votes)
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    • starky ultimate style avatar for user Delux
      Hey, you can see Part to Whole ratios as fractions. Lets say, the ratio of blue sofas to total amount of sofas is . You can also see it has 3/11. It doesn't work with part to part ratios though, so pay close attention before answering!
      (8 votes)
  • sneak peak green style avatar for user Nathan Campos
    Ratios are like fraction.
    (9 votes)
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  • aqualine tree style avatar for user VictoriaQueen5
    At , SO....... what you are saying is that ratios are written like time? Doesn't that ever get confusing?

    -ratios on a clock
    (8 votes)
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    • duskpin ultimate style avatar for user Ruchita Patel
      Ha ha! Ratios on a clock! Well, you can and can’t really get confused. As you may know, a day has 12 hours, so the hours on the clock goes till 12. But, if the the first number in the ratio is greater than twelve you know it isn’t a time you would see on a clock. But, if that’s not the case then you might get confused, unless someone specified.
      (4 votes)
  • starky sapling style avatar for user s8830411
    Can 400 percent be a ratio?
    (5 votes)
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  • female robot grace style avatar for user vanshika pahilwani
    At , are ratios the exact same as fractions? And what is the point of having two different ways of expressing the same thing?
    (2 votes)
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    • starky ultimate style avatar for user Serp Rivleau
      You could consider fractions to be a specific kind of ratio in the same way that a square is a specific kind of rectangle. The point of having two ways of expressing them is that they deal with information slightly differently:

      A fraction describes a single quantity based on its relationship to another quantity. In this example, the quantity of apples related to the quantity of total fruit. "2/5 of them are apples". This is clear and specific, and you can use it in equations.

      Ratios are more flexible. They can be more complicated than fractions and contain more information, but that also makes them harder to use. In the video's example, the ratio of apples to oranges could be expressed as 2:3. You could also add a third number for total fruit; Apples to oranges to total fruit are 2:3:5. Now you can tell just by looking at the numbers that all of the fruit are either apples or oranges, that the fraction that are apples is 2/5 and that the fraction that are oranges is 3/5. However, you couldn't use 2:3:5 in an equation the same way you can with a fraction because it doesn't identify what quantity you are measuring.

      Tl;dr: Ratios can give you more information about a complicated data set. Fractions can be used in equations but can't contain as much information. Simple ratios with only two terms can be written as fractions and are equivalent to them.
      (10 votes)
  • blobby green style avatar for user Humming Birb
    What is the difference of a ratio and a fraction?
    (3 votes)
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  • primosaur tree style avatar for user elizabeth.schock
    how to get back to begining
    (2 votes)
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  • duskpin seedling style avatar for user Abdulla aldhaheri
    (2 votes)
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Video transcript

Voiceover:Let's think about another scenario involving ratios. In this case, let's think about the ratio of the number of apples. Number of apples to ... Instead of taking the ratio of the number of apples to the number of oranges, let's take the number of apples to the number of fruit. The number of fruit that we have over here. And I encourage you to pause the video and think about that on your own. Well, how many total apples do we have? We have 2, 4, 6, 8 apples. So we're going to have 8 apples. And then how much total fruit do we have? Well we have 8 apples and we have 3, 6, 9, 12 oranges. So our total fruit is 8 plus 12. We have 20 pieces of fruit. So this ratio is going to be 8 to ... 8 to 20. Or, if we want to write this in a more reduced form, we can divide both of these by 4. 4 is their greatest common divisor. And so this is the same thing as a ratio. 8 divided by 4 is 2 and 20 divided by 4 is 5. So 2 to 5. Now, does this make sense? Well, if we divide ... If we divide everything into groups of 4. So ... Or if we divide into 4 groups, I should say. So 1 group, 2 groups, 3 groups, and 4 groups. That's the largest number of groups that we can divide these into so that we don't have to cut up the apples or the oranges. We see that in each group, for every 2 apples we have 1, 2, 3, 4, 5 pieces of fruit. For every 2 apples we have 5 pieces of fruit. This is actually a good opportunity for us to introduce another way of representing ... Another way of representing ratios, and that's using fraction notation. So we could also represent this ratio as 2 over 5. As the fraction 2 over 5. Whenever we put it in the fraction it's very important to recognize what this represents. This is telling us the fraction of fruit that are apples. So we could say 2/5 of the fruit ... Of the fruit ... Of the number of fruit, I guess I could say. Of number of fruit ... Of fruit is equal to the number of apples. Right, I'm just going to say 2/5 of fruit if we're just speaking in more typical terms. 2/5 of fruit are apples. Are, are apples. So, once again, this is introducing another way of representing ratios. We could say that the ratio of apples to fruit, once again, it could be 2 to 5 like that. It could be 2, instead of putting this little colon there we could literally write out the word to. 2 to 5. Or we could say it's 2/5, the fraction 2/5, which would sometimes be read as 2 to 5. This is also, when it's written this way, you could also read that as a ratio, depending on the context. In a sentence like this I would read this as 2/5 of the fruit are apples.