Dividing people into groups (1 Viewer)

SuxMATH

Member
Joined
Sep 25, 2014
Messages
32
Gender
Undisclosed
HSC
N/A
How many options are there for 25 students to divide into groups of 3,4,5 and 6?

My solution was 25C6 x 19C5 x 14C4 x 10C3 / 4! but not sure if right or wrong. Someone please clarify.
 

Drsoccerball

Well-Known Member
Joined
May 28, 2014
Messages
3,657
Gender
Undisclosed
HSC
2015
How many options are there for 25 students to divide into groups of 3,4,5 and 6?

My solution was 25C6 x 19C5 x 14C4 x 10C3 / 4! but not sure if right or wrong. Someone please clarify.
Why you dividing by 4! ?
 

Drsoccerball

Well-Known Member
Joined
May 28, 2014
Messages
3,657
Gender
Undisclosed
HSC
2015
If the groups where unable to be differentiated then you would divide by 4 not 4! but these groups have different numbers so therefore you can see the difference
 

sharoooooo

Active Member
Joined
Mar 30, 2015
Messages
297
Location
Online
Gender
Undisclosed
HSC
2015
just do it for each group of 3,4,5,6 and then add it all together?
 

InteGrand

Well-Known Member
Joined
Dec 11, 2014
Messages
6,109
Gender
Male
HSC
N/A
What is this Q asking exactly? The wording isn't clear. Does it mean how many ways can we divide them into a groups of 3, b groups of 4, c groups of 5, and d groups of 6, where 3a + 4b + 5c + 6d = 25, a, b, c, d (non-negative) integers?
 
Last edited:

braintic

Well-Known Member
Joined
Jan 20, 2011
Messages
2,137
Gender
Undisclosed
HSC
N/A
Of course, we are really dividing into groups of 3, 4, 5, 6 and 7.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top