8C3 - 3C3
I guess 55 is the answer.
permuatation ques
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neoreaves
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IMO 15
3 are linear points lets say a,b ,c
a ----b ----c
so there are 5 non linear points thus if we use side a-b then we can form 5 triangles.
with b-c similarly we can form 5 triangles
a-c = 5
so total = 15
3 are linear points lets say a,b ,c
a ----b ----c
so there are 5 non linear points thus if we use side a-b then we can form 5 triangles.
with b-c similarly we can form 5 triangles
a-c = 5
so total = 15
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eaakbari
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We have 8 points 3 collinear and 5 not collinear.
There are 3 possibilities.
Triangle is made from 5 non collinear points - 5C3
Triangle is made using one collinear point and 2 non collinear - 3C1 * 5C2
Triangle is made using two collinear points and 1 non collinear - 3C2 * 5C1
So answer is 5C3 + 3C1*5C2 + 3C2*5C1
I think you might have made a typo and written 8 instead of 5. Please clarify and give source of question
E
There are 3 possibilities.
Triangle is made from 5 non collinear points - 5C3
Triangle is made using one collinear point and 2 non collinear - 3C1 * 5C2
Triangle is made using two collinear points and 1 non collinear - 3C2 * 5C1
So answer is 5C3 + 3C1*5C2 + 3C2*5C1
I think you might have made a typo and written 8 instead of 5. Please clarify and give source of question
E
