At a party, everyone shook hands with everybody else. There were 4005 handshakes. How many people were at the party?
The number of handshakes between people is always the sum of 1+2+3+...+(n-1). n = number of people. Say there are 5 people, handshake between them will be 1+2+3+4 = 10 (try that with your friends 😀)
The sum of 1 to n of any number is (n(n+1))÷2. For example 1+2+3+4+5 = 15 and (5(5+1))÷2 = (5*6)÷2 = 15
So, to find the number of people at the party
(n(n+1))÷2 = 4005
Cross multiplying: n(n+1) = 4005x2 = 8010
Expanding the bracket: n² + n = 8010 n² + n - 8010 = 0
Solving that using the Almighty Formula (I don't think I need to go into that details)
n = 90 and -89
Ofcourse there can be negative people at the party so answer is 90 people
At a party, everyone shook hands with everybody else. There were 4005 handshakes. How many people were at the party?
The number of handshakes between people is always the sum of 1+2+3+...+(n-1). n = number of people. Say there are 5 people, handshake between them will be 1+2+3+4 = 10 (try that with your friends 😀)
The sum of 1 to n of any number is (n(n+1))÷2. For example 1+2+3+4+5 = 15 and (5(5+1))÷2 = (5*6)÷2 = 15
So, to find the number of people at the party
(n(n+1))÷2 = 4005
Cross multiplying: n(n+1) = 4005x2 = 8010
Expanding the bracket: n² + n = 8010 n² + n - 8010 = 0
Solving that using the Almighty Formula (I don't think I need to go into that details)
n = 90 and -89
Ofcourse there can be negative people at the party so answer is 90 people
Answer: 90
BY Riddles Repository - Answers
Warning: Undefined variable $i in /var/www/tg-me/post.php on line 283
Bitcoin is built on a distributed digital record called a blockchain. As the name implies, blockchain is a linked body of data, made up of units called blocks that contain information about each and every transaction, including date and time, total value, buyer and seller, and a unique identifying code for each exchange. Entries are strung together in chronological order, creating a digital chain of blocks. “Once a block is added to the blockchain, it becomes accessible to anyone who wishes to view it, acting as a public ledger of cryptocurrency transactions,” says Stacey Harris, consultant for Pelicoin, a network of cryptocurrency ATMs. Blockchain is decentralized, which means it’s not controlled by any one organization. “It’s like a Google Doc that anyone can work on,” says Buchi Okoro, CEO and co-founder of African cryptocurrency exchange Quidax. “Nobody owns it, but anyone who has a link can contribute to it. And as different people update it, your copy also gets updated.”
To pay the bills, Mr. Durov is issuing investors $1 billion to $1.5 billion of company debt, with the promise of discounted equity if the company eventually goes public, the people briefed on the plans said. He has also announced plans to start selling ads in public Telegram channels as soon as later this year, as well as offering other premium services for businesses and users.
