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| Math Central | Quandaries & Queries |
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Question from deciree, a student: Given 12 points, no 3 of them on a line with 6 red, 4 blue and 2 green points. thanks to lorraine! |
Deciree,
I can help get you started on a).
How many triangles have all green vertices?
The answer is clearly none since it takes three vertices to make a triangles.
How many triangles have all blue vertices?
There are 4 blue vertices and it takes 3 to form a triangle so the number of triangles with blue vertices is the number of ways of choosing 3 vertices from 4. That is 4 choose 3 which is 4.
How many triangles have all red vertices?
Now it's your turn.
Penny
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