Selection round 2019 Mymensingh Higher Secondary #7

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samiul_samin
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Joined:Sat Dec 09, 2017 1:32 pm
Selection round 2019 Mymensingh Higher Secondary #7

Unread post by samiul_samin » Sat Feb 02, 2019 12:05 am

Screenshot_2019-02-02-00-03-41-1.png
Here is a $4×3$ greed.Imagine a $6×4$ greed like this.In how many ways you can take three points from that imaginary greed so that the area of triangle formed by them will be zero?
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samiul_samin
Posts:1007
Joined:Sat Dec 09, 2017 1:32 pm

Re: Selection round 2019 Mymensingh Higher Secondary #7

Unread post by samiul_samin » Sat Feb 02, 2019 12:13 am

Caution
The points can be choiced diagonally :mrgreen:
Answer
$\fbox{132}$
Solve

Horizontally: $4×\dbinom{6}{3}$

Vertically: $6×\dbinom{4}{3}$

Diagonally: $6×\dbinom{4}{3}+4\dbinom{3}{3}$

Total=$132$

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