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Lachlan1996

  • one year ago

Help with mathematical combinations please. Points A, B, C, D, E, F, G, H, and I are arranged in two rows such that we have A - B - C - D - E and F - G - H - I How many triangles can be formed having vertices chosen from these points? How many of these triangles have the point A as one of their vertices?

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  1. Lachlan1996
    • one year ago
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    Sorry it is A - B - C - D - E F - G - H - I

  2. Lachlan1996
    • one year ago
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    Awesome thank you for visiting unklerhaukus!!!

  3. UnkleRhaukus
    • one year ago
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    |dw:1360476356312:dw|

  4. Lachlan1996
    • one year ago
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    Yes they are to act as the vertices of triangles.

  5. UnkleRhaukus
    • one year ago
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    so either two points are from the top line (and one from the bottom line) or one point is from the top line (and two from the bottem line)

  6. Lachlan1996
    • one year ago
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    Hmm i see, let me try that, i wasnt sure how to interpret it.

  7. UnkleRhaukus
    • one year ago
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    because if all three points were on the same line , you couldn't make a triangle

  8. Lachlan1996
    • one year ago
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    Yes that appears to work, 5C1 x 4C2 and 5C2 x 4C1 which adds to 70

  9. Lachlan1996
    • one year ago
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    Though can I ask how you determine how to do these questions? I havent really got a problem solving type of mind, so i find it difficult to think laterally.

  10. UnkleRhaukus
    • one year ago
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    \[^nC_k = \frac{n!}{k!(n-k)!}\]

  11. Lachlan1996
    • one year ago
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    No i understand the general formula of the combination theory. I just often have difficulty understanding how I am meant to approach the question, what guidelines I need to follow.

  12. Lachlan1996
    • one year ago
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    Once you had explained those guidelines i knew exactly what to do, i just dont know how to determine the parameters to follow.

  13. UnkleRhaukus
    • one year ago
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    i like to start with a picture usually

  14. Lachlan1996
    • one year ago
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    Are there any other tricks you can use to figure out whats going on? or is it just trying to pull apart the question, and making assumptions to rules.

  15. UnkleRhaukus
    • one year ago
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    im not sure how to answer that,

  16. Lachlan1996
    • one year ago
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    Ah well, im sure i'll just have to pick it up as I go. You've helped enough already. Thank you very much for the assistance. I wish you a good afternoon. Thank you for the help mate, I appreciate the effort :) Have a good one mate, and stay well!

  17. UnkleRhaukus
    • one year ago
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    sometimes rewriting the question into a simpler form can help

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