SOLUTION: How many triangles can be made in a 4 by 20 grid in which the triangles have an area greater than Zero? I figured out how many you can make when the trianes have zero area. That

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Question 972697: How many triangles can be made in a 4 by 20 grid in which the triangles have an area greater than Zero?
I figured out how many you can make when the trianes have zero area. That would be 80 choose 3 which is 82160 but I can't figure it out

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


No. is correct because that is choosing 3 out of 80 regardless of order AND without replacement. The only way you get a zero area triangle is if two or three of the chosen points are the same point, which is to say that the selection is made WITH replacement.

John

My calculator said it, I believe it, that settles it