Respuesta :
Given:
Total number of people = 10
To find:
The number of ways in which 10 people can be divided into three groups of 2, 3, and 5 people respectively.
Solution:
We know that the number of ways to select r items form n times is:
[tex]^nC_r=\dfrac{n!}{r!(n-r)!}[/tex]
The number of ways to select 2 people from 10 is [tex]^{10}C_2[/tex].
The number of remaining people is [tex]10-2=8[/tex].
The number of ways to select 3 people from 8 is [tex]^{8}C_3[/tex].
The number of remaining people is [tex]8-3=5[/tex].
The number of ways to select 5 people from 5 is [tex]^{5}C_5[/tex].
Now, the total number of ways is:
[tex]Total=^{10}C_2\cdot ^{8}C_3\cdot ^{5}C_5[/tex]
[tex]Total=\dfrac{10!}{2!(10-2)!}\cdot \dfrac{8!}{3!(8-3)!}\cdot \dfrac{5!}{5!(5-5)!}[/tex]
[tex]Total=\dfrac{10\times 9\times 8!}{2\times 1\times 8!}\cdot \dfrac{8\times 7\times 6\times 5!}{3\times 2\times 1\times 5!}\cdot 1[/tex]
[tex]Total=45\cdot 56\cdot 1[/tex]
[tex]Total=2520[/tex]
Therefore, the total number of ways is 2520 to divide 10 people into three groups of 2, 3, and 5 people respectively.
