5 people

121 people are at the event

Iamdagreatguy:
Weekend brain drill. The first to get the answer wins a prize:

At a birthday party, everyone shook hands with everybody else. There were 120 handshakes. How many people were at the party?

Its 5. Using factorials.5!=120

being:
16 dudes made d party!

correct!

x-1 + x-2 + x-3 + ... + 1 = 120

6 people.
formula used 1 x (n-1)!

if 1 x (n-1)! =120
(n-1)! = 120
(n-1)! = 120
n-1 = 5
n= 6

256 person

There can't be 120 handshakes.

U nor c as God catch u? Na my brain u wan drill. Smeone shld spit d answr make we paste am jor

nC2=120 n/2(n-2)=120 Oya complete am I don tire..

12×10

J ke Ahn ahn

Jamexjulius:
J

16

This nah Permutation OOOOO.

1+2+3+4+5+6+7+8+9+10++11+12+13+14+15=120 ANSWER=16 THIS IS BECAUSE THE LAST PERSON CAN'T SHAKE HIMSELF

120 divided by 2 =60

I'll go for 5 5!=120 @

There are 6 persons at the party.
It is (n-1)!=120
(n-1)!= 5!
n=6

yorme:
The Answer is 5. Handshakes between 5 people will result in a total of 120 handshakes.

5! = 120 handshakes.

yorme:
The Answer is 5. Handshakes between 5 people will result in a total of 120 handshakes.

5! = 120 handshakes.

this must be the ans because its simple permutation///

Iamdagreatguy:
Weekend brain drill. The first to get the answer wins a prize:

At a birthday party, everyone shook hands with everybody else. There were 120 handshakes. How many people were at the party?

16 guests. Use combinatorial.

1 person shakes 0 people.
2 persons involve 1 handshake
3 persons involve 3 handshakes
4 persons involve 6 handshakes
5 persons involve 10 handshakes . . . . .
16 persons involve 120 handshakes

16 people

n (n-1)
------- = 120
2

16 (15)
-------- = 120
2


this formula is used when one person or station connects to every other person or station.

5 people 5! Handshake = 120 handshake

.

Iamdagreatguy:
Weekend brain drill. The first to get the answer wins a prize:

At a birthday party, everyone shook hands with everybody else. There were 120 handshakes. How many people were at the party?

5 ppl because 5! = 120

x persons will shake x persons =120 times
x+x=120
2x=120
x=120÷2=60persons present in d party.

Mathematically, this is just permutation
X!/(X-R!R!) equals 120
Where
R is equal to 2
If x! Divides X-2!
We have x times x-1 divided by 2 equals 120
Which is x squared minus x equals 240
Which is a quadratic equation with a,b,c equal to 1, -1 and -240

Solving we have,
X equals 16 and -15
Since we can't have -15 people
Your answer is 16



Where is my gift OP?

I Am back again nd the Ans is either 5 or 6...

I Am back again nd the Ans is either 5 or 6 people @d party.....

16 is d ans . Rep futo mth dept 500 level
16!/(16-2)!=120

Na dis simple maths dey make ppl stumble lyk dis hmm if u post 16 u r correct

240 2 people, one handshake 120 handshakes × 2= 240