Inspired by Hana Nakkache and because I like 2017!

Probability Level 3

With 2017 2017 points on a circle how many triangles can I form by connecting these points? If the answer is a x x digit whole number, submit your answer as x − 1 x-1

Inspiration


The answer is 9.

Sathvik Acharya by Sathvik Acharya , 17, India

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1 solution

Hana Wehbi
Jun 19, 2017

The formula for y y triangles using n n points is n ( n − 1 ) ( n − 2 ) 6 = ( 2017 ) ( 2016 ) ( 2015 ) 6 = 1 , 365 , 589 , 680 \frac{n(n-1)(n-2)}{6}= \frac{(2017)(2016)(2015)}{6} =1,365,589,680 which is a 10 10 digit number.

Thus x − 1 = 10 − 1 = 9 x-1= 10-1= 9

3 Helpful 0 Interesting 0 Brilliant 0 Confused

@Hana Nakkache Is there any prove for the formula

Sumukh Bansal - 3 years, 6 months ago

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There must be, lol :)

Hana Wehbi - 3 years, 6 months ago

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