66
190
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.
If there are seven people, then the number of handshakes is 7*6/2 = 21
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.
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.
190
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.
If there are seven people, then the number of handshakes is 7*6/2 = 21
Sixty-six unique, distinct handshakes.
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.
Type your answer here... 6
50*49/2 = 1225
There will be 45 handshakes (assuming that each person doesn't repeat who they shake hands with). Use the following formula for this one (n*(n-1))/2 where n is number of people...so if 10 people its (10 x 9) / 2 = 45 handshakes, if 7 people its (7 x 6) / 2 = 21 handshakes etc.
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.
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.
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.
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.