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Probability - Please show solution

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Probability - Please show solution

by DCJ » Wed Oct 07, 2009 4:50 pm
A basket contains 5 apples of which 1 is spoiled and the rest are good. If Henry is to select 2 apples from the basket simultaneously and at random, what is the probability that the 2 apples selected will include the spoiled apple?

1/5

3/10

2/5

1/2

3/5

Ans: 2/5
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by sunnyjohn » Wed Oct 07, 2009 6:27 pm
he has to select two apples and two apples should include the rotten apple.

so -
desired case:
he needs to select 1 apple from 1 rotten apple
he needs to select 1 apple from 4 good apple.

total cases:
he needs to select 2 apple from 5 apple.

1C1*4C1/5C2

1*4*2/5*4==> 2/5
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by sanjana » Thu Oct 08, 2009 3:11 am
P(Seclting 2 spoilt apples) = 1 - p(Selecting 2 good apples)

= 1 - 4c2/5c2
=4/10
=2/5
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