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Q: How many handshakes if 20 people shake hands with every other person in the room?
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If there are 8 people at a party and every person shakes hands with everyone else at the party how many handshakes will there be?

There will be 28 handshakes. If you ask each person how many handshakes they had they will tell you 7 making 7 x 8 = 56 handshakes in all. But every hand involves two people, so every handshake has been counted twice, thus there are 56 / 2 = 28 handshakes in all.


There are five people in a room Each person shakes the hand of every other person exactly once How many handshakes are exchanged?

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.


There are 3 people at a party If each person must shake hands with every other person at the party exactly once how many handshakes will there be?

With 3 people, there are only 3 handshakes: AB, AC, and BC. Where it gets interesting is at a party with, say, 10 people ... 45 handshakes. Or in the US Senate when all 100 Senators are present ... 4,950 handshakes.


If There are 3 people at a party If each person must shake hands with every other person at the party exactly once how many handshakes will there be?

3. AB, BC and CA.


If each of seven persons in a group shakes hands with each of the other six persons then a total of forty-two handshakes occurs?

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.

Related questions

there are 3 people at a party if each person mis shake hands with every person at the party exactly once how many handshakes will there be?

So, there will be 3 handshakes among the 3 people at the party.


If there are 8 people at a party and every person shakes hands with everyone else at the party how many handshakes will there be?

There will be 28 handshakes. If you ask each person how many handshakes they had they will tell you 7 making 7 x 8 = 56 handshakes in all. But every hand involves two people, so every handshake has been counted twice, thus there are 56 / 2 = 28 handshakes in all.


How many handshakes if 25 people shake hands with every other person in room?

Each person will shake hands with every other person, except himself. If there are 25 people, each person will shake hands with 25-1 people, or 24. The number of times each person will shake hands with another, will be 25x24. The number of handshakes will be half of that, as each handshake is between two persons. The formula, in other words, is x(x-1)/2, where x is the number of people. With 25 people, it will be 25x24/2 = 300 handshakes.


How many handshakes if 4 people shakes hands with every other person in the room?

Type your answer here... 6


If at a party there are twelve people present Everyone has to shake hands exactly once with every other person How many handshakes are necessary?

Sixty-six unique, distinct handshakes.


How many handshakes if 6 people shakes hands with every other person in the room?

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.


There are five people in a room Each person shakes the hand of every other person exactly once How many handshakes are exchanged?

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.


There are 6 people at a party If each person must shake hands with every other person at the party exactly once how many handshakes will there be?

15


There are 3 people at a party If each person must shake hands with every other person at the party exactly once how many handshakes will there be?

With 3 people, there are only 3 handshakes: AB, AC, and BC. Where it gets interesting is at a party with, say, 10 people ... 45 handshakes. Or in the US Senate when all 100 Senators are present ... 4,950 handshakes.


If There are 5 people at a party Each person must shake hands once with every other person at the party How many handshakes does it take to do this?

10 times


If There are 3 people at a party If each person must shake hands with every other person at the party exactly once how many handshakes will there be?

3. AB, BC and CA.


There are 6 people at a party If each person must shake hands with every other person at the party exactly once, how many handshakes will there be?

The first person must shake hands with 5 other people. The next must shake hands with 4 other people, since you exclude the first person. Keep going and you'll find that there will be 5+4+3+2+1=15 handshakes. Numbers like this are called triangular numbers.