Question 1160571: There are 5 computers in a store. Among them, 3 are brand new, and 2 are
refurbished. How many ways are there to choose 3 computers that include 1
refurbished computer!
Found 2 solutions by saw, Edwin McCravy:
Answer by saw(34)   (Show Source):
You can put this solution on YOUR website! Let b = brand new
Let r = refurbished
3b+2r = 5
b+b+b+r+r = 5
b+b+r
b+r+b
r+b+b
nPr = n!/(n-r)! = 3!/(3-1)! = 3!/2! = 6/2 = 3
There are 3 ways to choose 3 computers that include 1 refurbished computer.
Answer by Edwin McCravy(20054)  (Show Source):
You can put this solution on YOUR website! There are 5 computers in a store. Among them, 3 are brand new, and 2 are
refurbished. How many ways are there to choose 3 computers that include 1
refurbished computer!
Choose the 1 unfurbished one from the 2.
(2 refurbished CHOOSE 1) = C(2,1) = (2∙1)/1! = 2 ways.
For each of those wats, we choose the 2 brand new ones from the 3.
(3 brand new ones CHOOSE 2) = C(3,2) = (3∙2∙1)/2! = 6/2 = 3 ways.
We multiply (because it's an "AND" situation).
2∙3 = 6 ways.
Checking:
If the 3 brand new ones are A,B, and C and the 2 refurbished ones are X and Y,
we can choose:
1. A,B,X
2, A,B,Y
3. A,C,X
4. A,C,Y
5. B,C,X
6. B.C.Y
Edwin
Edwin
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