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11 Mar 2010 18:27:56 IST

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A bag contains tickets numbered 1,2,3..........50 of which 5 tickets x1,x2,x3,x4,x5 are drawn at

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A bag contains tickets numbered 1,2,3..........50 of which 5 tickets x1,x2,x3,x4,x5 are drawn at random and arranged in ascending order of magnitude x1<x2<x3<x4<x5.what is the probability that x3=30?

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Dasvidaniya

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11 Mar 2010 18:36:30 IST

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ur question is complete ?

Kirthi

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11 Mar 2010 18:43:21 IST

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i hav edited it

Transmigrator

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11 Mar 2010 19:29:34 IST

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For x₃ to be = 30, x₁ & x₂ must be less than 30 along with x₄ & x₅ being greater than 30.....

Now, No. of all possible selections = ⁵⁰C₅ = a

No of selections such that x₃ is equal to 30 = ²⁹C₂* ²⁰C₂= b

Hence, Probability = b/a = (U calculate it)

Deepak Aggarwal

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12 Mar 2010 11:27:59 IST

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Let the third ticket be 30.

So, first two tickets have to be less than 30. There are 29 tickets less than 30 out of which two can be selected in ²⁹C₂ ways. Third ticket 30 can be selected in 1 way only. The remaining two are to be selected from 20 tickets numbered greater than 30 which can be selected in ²⁰C₂ ways.

Five tickets can be selected from 50 tickets in ⁵⁰C₅ ways.

So, req. probability = ²⁹C₂X 1 X ²⁰C₂ / ⁵⁰C₂ = 551 / 15134 (Ans)

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12 Mar 2010 11:32:48 IST

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@Deepak: U've done a little typing mistake in the last line....................Its ⁵⁰C₅ in the denominator, not ⁵⁰C₂...........

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