0 Deepak Bora Asked: July 4, 20202020-07-04T13:30:59+05:30 2020-07-04T13:30:59+05:30In: Competition At a party, everyone shook hands with everybody else. There were 66 handshakes. How many people were at the party?? 0 This question is quite difficult , which can come in olympial or any other compitative exam. logical reasoningolympiad Share Facebook Related Questions 12, 11, 13, 12, 14, 13, .........… What number should come next? can you find the number of triangles in this figure? Prove that:- (a + b) (b + c) (c + a) ≥ 8abc. What is the value of √.4 1 Answer Voted Oldest Recent Deepak Bora 2020-07-04T13:40:44+05:30Added an answer on July 4, 2020 at 1:40 pm no of handshakes =nC2=n!/(n-2)!(2)! =n(n-1)(n-2)!/(n-2)!2=n(n-1)/2= n(n-1)=132=12×11 so n=no of handshakes =12 here we used combinations because in permutations AB is different from BA but in combinations both are same. Note -: Since if two persons hand shake it means both shake their hands with each other. So here A shakes hand with B is same as B shakes hand with a. 0 Reply Share Share Share on Facebook Share on Twitter Share on LinkedIn Share on WhatsApp Leave an answerLeave an answerCancel reply Featured image Select file Browse Add a Video to describe the problem better. Video type Youtube Vimeo Dailymotion Facebook Choose from here the video type. Video ID Put Video ID here: https://www.youtube.com/watch?v=sdUUx5FdySs Ex: "sdUUx5FdySs". Click on image to update the captcha. Save my name, email, and website in this browser for the next time I comment.