Safari321
Six students are pairing up to play tennis.In how many different ways can they pair up?
Delete
Share
This Question is Closed
mridrik
Best Response
You've already chosen the best response.
1
This is not permutations luis, it's combinations
Safari321
Best Response
You've already chosen the best response.
0
720 ways?
mridrik
Best Response
You've already chosen the best response.
1
he is wrong
Safari321
Best Response
You've already chosen the best response.
0
oh
mridrik
Best Response
You've already chosen the best response.
1
he was saying that if Anne and Bill paired up, it would be different than Bill and Anne pairing up
Safari321
Best Response
You've already chosen the best response.
0
oh
mridrik
Best Response
You've already chosen the best response.
1
it can be written as nCr which means n choose r, where n is larger. so in this case it is 6 choose 2, and to find the answer, you plug them into this formula:
|dw:1331001470884:dw|
anonymous
Best Response
You've already chosen the best response.
0
pick one person, person A then their are 5 choices for partners. after that pick another, there are 3 choices of partners. then no choices
Safari321
Best Response
You've already chosen the best response.
0
so there's a formula for combinations?
mridrik
Best Response
You've already chosen the best response.
1
! means factorial, and you multiply by all the natural numbers less than the number in front of the !, so for 6! it would be, 6 x 5 x 4 x 3 x 2 x 1
Safari321
Best Response
You've already chosen the best response.
0
then that'll be the outcome of the of combinations?
mridrik
Best Response
You've already chosen the best response.
1
6! = 720, then we divide by 2! (which is just 2) times (6-2)!
2 x 4! = 4 x 3 x 2 x 2 x 1 = 48, so the answer is 720 divided by 48 which simplifies to 15
Safari321
Best Response
You've already chosen the best response.
0
okay mridrick thanks!
mridrik
Best Response
You've already chosen the best response.
1
you're welcome
Safari321
Best Response
You've already chosen the best response.
0
:)
mridrik
Best Response
You've already chosen the best response.
1
:D