2.In how many ways can a committee of 5 be formed from 7 juniors and 6 seniors if the
committee must have 3 juniors?
Answers
Given : a committee of 5 be formed from 7 juniors and 6 seniors if the
committee must have 3 juniors
To Find : Number of ways
Solution:
Junior = 7
Senior = 6
committee must have 3 juniors
committee of 5
3 junior + 4 junior + 5 junior
= ⁷C₃*⁶C₂ + ⁷C₄*⁶C₁ + ⁷C₅*⁶C₀
= 35 * 15 + 35 * 6 + 21*1
= 35 * 21 + 21
= 36 * 21
= 756
756 ways committee can be formed
Learn More:
in how many ways can the letters of the word 'cinema' be arranged ...
brainly.in/question/12528704
In how many ways can the letters of the word 'SEEDING' be ...
brainly.in/question/15386861
9.How many arrangements can be made out of the letters of the ...
brainly.in/question/12222658
According to the Question
We need to select a committee of 5 from 5 juniors and 7 seniors.
Now 3 of seniors are to be selected.
So, that we need 2 members from total of 5 juniors and 4 seniors.
Case 1
Where both are juniors
So, we need 5 C 2 i.e. 10 cases
Case 2
Where 1 is junior and other is senior
So we need 5 C 1 +4 C 1 i.e. 9
Case 3
Where both are seniors
Here we need 4 C 2 i.e. 6
So total cases
=10+9+6
So, 25 are the total cases