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John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical

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Kudos [?]: 135771 [0], given: 12708

John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical [#permalink]

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New post 26 Nov 2017, 08:08
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John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical pencils and 9 wood pencils. If John reaches into the drawer and selects randomly how many writing tools must he remove in order to ensure that he will select one of each type?

A. 23
B. 21
C. 20
D. 15
E. 4
[Reveal] Spoiler: OA

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Kudos [?]: 135771 [0], given: 12708

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Joined: 02 Sep 2009
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Kudos [?]: 135771 [0], given: 12708

Re: John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical [#permalink]

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New post 26 Nov 2017, 08:10
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Bunuel wrote:
John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical pencils and 9 wood pencils. If John reaches into the drawer and selects randomly how many writing tools must he remove in order to ensure that he will select one of each type?

A. 23
B. 21
C. 20
D. 15
E. 4


Check other Worst Case Scenario Questions from our Special Questions Directory to understand the concept better.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
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Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


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Kudos [?]: 135771 [0], given: 12708

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Re: John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical [#permalink]

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New post 26 Nov 2017, 08:29
D. 15
Suppose he selects 5 black pens and then 6 blue pens and 3 mechanical pencils. To reach the wood pencil he should have chosen 14 items already and with the 15th item he chose he would have chosen one of each type.
Hence D


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Help with kudos if u found the post useful. Thanks

Kudos [?]: 38 [0], given: 89

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Re: John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical [#permalink]

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New post 26 Nov 2017, 08:43
Sasindran wrote:
D. 15
Suppose he selects 5 black pens and then 6 blue pens and 3 mechanical pencils. To reach the wood pencil he should have chosen 14 items already and with the 15th item he chose he would have chosen one of each type.
Hence D


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hi..

your approach is correct but you could not take it to logical end..

Solution

5 black pens, 6 blue pens, 3 mechanical pencils and 9 wood pencils
we have to take the worst case scenario, so here think that you will get the LEAST numbered thing in the end, which here is 3 mechanical pencils..

so he picks up 5 black pens, 6 blue pens, 3 mechanical pencils and 9 wood pencils = 5+6+9=20
and then he picks up a mechanical pencil so 21

B
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Kudos [?]: 6140 [0], given: 121

Re: John has a drawer containing 5 black pens, 6 blue pens, 3 mechanical   [#permalink] 26 Nov 2017, 08:43
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