Question 574595: Sow all work. Mary purchased a package of 18 different plants, but she only needed 12 plants for planting. In how many ways can she select the 12 plants from the package to be planted?
Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! Use the combination formula (since order of the plants chosen does not matter)
C(n,r) = (n!)/(r!(n-r)!)
C(18,12) = (18!)/(12!*(18-12)!)
C(18,12) = (18!)/(12!*6!)
C(18,12) = (18*17*16*15*14*13*12!)/(12!*6!)
C(18,12) = (18*17*16*15*14*13)/(6!)
C(18,12) = (18*17*16*15*14*13)/(6*5*4*3*2*1)
C(18,12) = (13366080)/(720)
C(18,12) = 18564
So there are 18564 different ways
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Mary purchased a package of 18 different plants, but she only needed 12 plants for planting. In how many ways can she select the 12 plants from the package to be planted?
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Ans: 18C12 = 18C6 = 18564
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Cheers,
Stan H.
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