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4 girls and 8 boys are standing together. In how many ways can a 7- person committee be selected from the group if at least 2 girls must be included?

 Jan 13, 2020
 #1
avatar+22108 
+1

I'll try to answer this....

   how many ways can you choose 2 girls ?   4 C 2 = 6 ways

       then you ned to choose 5 more people for the committee from the remaining 10 people     10 C 5 = 252 ways

6  x  252 = 1512 ways to form committee

 

Hmmmmm....that does not seem correct.....

 Jan 13, 2020
edited by ElectricPavlov  Jan 13, 2020
 #2
avatar+109739 
+1

2, 3 or 4 girls must be selected

 

If 2 are selected we have  C(4,2) * C(8, 5)

If 3 are selected, we have C(4,3) * C(8, 4)

If 4 are selected, we have C(4,4) * C(8, 3)

 

So we have

 

C(4,2)*C(8,5)  + C(4,3) * C(8,4)  + C(4,4)* C(8,3)   =  672 ways

 

 

 

 

cool cool cool

 Jan 13, 2020

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