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Q: How many hand shakes if 12 people shake hands with every other person in room?

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First person shakes hands 19 times, second person 18 etc, a total of 190.

10 times

manicurist

The two hands make an angle of 155 degrees (and 205 degrees).

For everyone to shake hands with everyone else, there are 21 handshakes. (below copied from my answer of a similar question) This is an arithmetic progression and can be solved with the equation Sn=(1+(n-1))(n-1)/2 where Sn is the total sum of handshakes for n people. NB: I have used n-1 instead of n in the equation for the sum of an arithmetic progression, because you're not really going to shake hands with yourself, so you don't include the nth term, in this case 7. Alternatively, you can solve this geometrically by drawing a heptagon, drawing lines between all the vertices, and then adding all the lines up.

Related questions

If there are 6 people in a room, and each person shakes hands with every otherperson in the room, then there will be 15 separate and distinct handshakesbetween different pairs of people.

25 shakes

The correct answer is 21. The first person shakes hands with the other 6 people. The second person shakes hands with 5 people because they already shook hands with the first person. The third person shakes hands with 4 people because they already shook hands with the first and second person. The fourth person shakes hands with 3 people because they already shook hands with the first, second, and third. The fifth person shakes hands with 2 people because they already shook hands with the first, second, third, and fourth person. The sixth person shakes hands with the seventh person because the rest have already shaken hands with them. The seventh person doesn't have anyone else to shake hands with. So the total would be 21...

The answer is 21 handshakes because the first person shakes hands with the other 6 people. The second person shakes hands with 5 people because they already shook hands with the first person. The third person shakes hands with 4 people because they already shook hands with the first and second person. The fourth person shakes hands with 3 people because they already shook hands with the first, second, and third. The fifth person shakes hands with 2 people because they already shook hands with the first, second, third, and fourth person. The sixth person shakes hands with the seventh person because the rest have already shaken hands with them. The seventh person doesn't have anyone else to shake hands with. Therefore the answer is 21 handshakes.

Type your answer here... 6

If there are seven people, then the number of handshakes is 7*6/2 = 21

Assuming that each person shakes hands with every other person, there are 12 people. Let n be the number of people. Then each person shakes hands with (n-1) people and if you ask every person how many hand shakes they made and total them you will get a total of n(n-1) handshakes. However, each handshake involves two people and has been counted twice - once by each person that shook hands - thus number of hand shakes is half of this, giving: n(n-1)/2 = 66 ⇒ n(n-1) = 132 ⇒ n2 - n - 132 = 0 ⇒ (n - 12)(n + 11) = 0 ⇒ n = 12 or -11 You can't have -11 people, therefore there are 12 people.

First person shakes hands 19 times, second person 18 etc, a total of 190.

if there are 2 people in a room and each one shakes hands once with every other person in the room, how many hand shakes are there?... answer( 1 handshake) pretty easy isn't it? if there are 3 people in a room and everyone shakes hands with everyone else, how many hand shakes are there? answer( three handshakes) now how many handshakes will there be for 5 people in a room? its your time to shyne...

105 ( First person shakes 14 different hands, second shakes 13 etc etc down to 14th shakes 1 hand. Sum of 1 to 14 = 105.)

Perhaps 9,900 As in you shake with 99 other people, then the next person does the same. So each of the 100 people do 99 shakes. 99 x 100 = 9,900

Everyone shakes hands with 4 other people. Since there are 5 people in the room this would suggest there are 5*4 = 20 handshakes. However, you would then be double counting handshakes: A shaking hands with B and B shaking hands with A is, in reality, only one handshake. Thus there are 5*4/2 = 10 handshakes in all.

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