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George's drawer has 10 loose black socks, 15 loose blue socks, and 8

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George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 22 Jan 2015, 08:09
1
8
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A
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  25% (medium)

Question Stats:

73% (00:53) correct 27% (01:02) wrong based on 233 sessions

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George's drawer has 10 loose black socks, 15 loose blue socks, and 8 loose white socks. If George takes socks out of the drawer at random, how many would he need to take out to be sure that the removed socks include at least one matching pair ?

A. 3
B. 4
C. 9
D. 5
E. 31

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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 22 Jan 2015, 14:44
2
in worst scenario he will draw three different color socks and 4th draw will be a matching pair.
Answer is B

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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 22 Jan 2015, 23:09
1
30 secs

Ans B = 4

600 level ... Really?
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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 24 Jan 2015, 16:03
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We plan for the worst case scenario. Let K, B, W = black, blue, white (respectively). Say we draw KBW. No matter what we pick next, we will have a matching pair. The answer is 4 (B).
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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 30 Sep 2015, 09:09
1
Answer = B

Worst case scenario:
First Pick = Blue
We only have one sock, so no match.
Second Pick = Black
Darn, a different color, still no match.
Third Pick = White
What are the odds, still no match.
Fourth Pick = Black
Hurrah, we now have a pair of black socks!

You can substitute the color of the fourth pick with either blue or white and the answer still hold true, we would have a match.
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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 01 Oct 2015, 08:18
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Answer is 4

As there are 3 categories, fourth draw will match one of the earlier drawn category.
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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 03 Oct 2015, 04:00
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Bunuel wrote:
George's drawer has 10 loose black socks, 15 loose blue socks, and 8 loose white socks. If George takes socks out of the drawer at random, how many would he need to take out to be sure that the removed socks include at least one matching pair ?

A. 3
B. 4
C. 9
D. 5
E. 31

Kudos for a correct solution.


For 1 matching pair the worst scenario is that he picks 3 socks and all 3 are different color

but in that case 4th sock picked has to be a repeated color thereby making a pair

Hence, Minimum socks needed to be picked = 4

Answer: option B

Bunuel: you might want to add an OA in this question as official answer is still not provided.
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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 03 Oct 2015, 04:47
1
Bunuel wrote:
George's drawer has 10 loose black socks, 15 loose blue socks, and 8 loose white socks. If George takes socks out of the drawer at random, how many would he need to take out to be sure that the removed socks include at least one matching pair ?

A. 3
B. 4
C. 9
D. 5
E. 31

Kudos for a correct solution.



My Solution:

As we have socks of 3 different colours, in the first three picks we can take out socks of any colour. So to be sure that we have a pair of socks we need to pick forth one. It will pair up with any of the first three socks we chose.

So IMO, answer is 4. Choice B

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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8  [#permalink]

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New post 07 Aug 2018, 08:52
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Re: George's drawer has 10 loose black socks, 15 loose blue socks, and 8 &nbs [#permalink] 07 Aug 2018, 08:52
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