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catgirl17 Group Title

you own 9 pairs of jeans and are taking 4 of them on vacation. in how many ways can you choose 4 pairs of jeans from the 9?

  • 2 years ago
  • 2 years ago

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  1. Ledah Group Title
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    Seeing as this is probability I'm going to say that there are 36 or 45 choices on pants you can pick. hope this helps.. there are so many ways you can do this

    • 2 years ago
  2. sritama Group Title
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    9c4

    • 2 years ago
  3. mathplane Group Title
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    This is an example of a combination problem... First, establish how many ways there are to pack the jeans.... There are 9 choices for the 1st pair of pants... 8 remaining choices for the 2nd pair... 7 remaining for the 3rd pair... And, 6 remaining choices for the 4th pair.... this implies 9 x 8 x 7 x 6 permutations.... However, ORDER DOES NOT MATTER.. Therefore, we must divide to get rid of all the "double counting"... (i.e. choosing 1469 pants is the same as 4169 or 9146... in each case, you packed 1-4-6-9...)... So, your final solutions is (9 x 8 x 7 x 6)/(4!) = 126

    • 2 years ago
  4. mathplane Group Title
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    Using the formula for combinations: 9C4 = 9!/5!4! = 126

    • 2 years ago
  5. Ledah Group Title
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    Totally thought of something else.......

    • 2 years ago
  6. catgirl17 Group Title
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    how did you get 126?

    • 2 years ago
  7. Ledah Group Title
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    Thats what I'm wondering

    • 2 years ago
  8. catgirl17 Group Title
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    cause when you do 9x8x7x6=3024 and then if you divide it by 4 you get 756

    • 2 years ago
  9. mathplane Group Title
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    No, you must divide by 4! 3024/24

    • 2 years ago
  10. catgirl17 Group Title
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    where did you get 24 from?

    • 2 years ago
  11. mathplane Group Title
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    4! = 4 x 3 x 2 x 1 = 24

    • 2 years ago
  12. jsoeung Group Title
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    The exclamation mark isn't yelling, it's called a factorial :) so N! would be N multiplied by all the numbers that come before it

    • 2 years ago
  13. jsoeung Group Title
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    Just fyi

    • 2 years ago
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