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by rakeshd347 » Sat Oct 19, 2013 7:55 pm
If a box contains 10 red pills, 5 blue pills, and 12 yellow pills, what is the least number of pills one must extract from the box to ensure that at least three pills of each color are among those extracted?
12
17
18
23
25

OA is E
Last edited by rakeshd347 on Sun Oct 20, 2013 1:33 am, edited 1 time in total.
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Source: — Problem Solving |

by theCodeToGMAT » Sat Oct 19, 2013 8:14 pm
Considering worst case...
10 + 12 + 3 = 25

Answer [spoiler]{E}[/spoiler]?
Last edited by theCodeToGMAT on Mon Oct 21, 2013 6:44 am, edited 1 time in total.
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by Uva@90 » Sat Oct 19, 2013 8:22 pm
Consider the worst case scenario where he removes 12 yellow pills(which contributes more) then 10 red pills then 3 blue pills.

i.e. 12+10+3 =25

SO Answer is E

Regards,
Uva.
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by [email protected] » Sat Oct 19, 2013 11:29 pm
Hi rakeshd347,

Uva@90 has described this type of question in a great way: the "worst case scenario." In questions that ask about what it would take to "ensure" or "guarantee" an outcome, you have to consider the "worst case scenario."

That "worst case scenario" here would be if you maximized the number of 2 colors before you got 3 of the final color:

12 yellows + 10 reds......+ 3 blues = 25

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Rich
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by GMATGuruNY » Sun Oct 20, 2013 4:02 am
rakeshd347 wrote:If a box contains 10 red pills, 5 blue pills, and 12 yellow pills, what is the least number of pills one must extract from the box to ensure that at least three pills of each color are among those extracted?
12
17
18
23
25

OA is E
As noted above, this is a WORST-CASE SCENARIO problem.
To GUARANTEE that 3 of each color are chosen, we must determine the worst-case scenario: the greatest number of marbles that can be removed WITHOUT choosing at least 3 of each color.

If all of the yellow pills and all of the red pills are removed first, the number of pills removed = 12+10 = 22.
Since there are more yellow pills and red pills than blue pills, 22 is the maximum number of pills that can be removed without choosing at least 3 of each color.

To remove at least 3 of each color, 3 blue pills must now be chosen, yielding the following total:
22+3 = 25.

The correct answer is E.

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by sahilchaudhary » Mon Oct 21, 2013 6:43 am
We have to take the worst case.
12+10+3 = 25.

So, the answer is E.
Sahil Chaudhary
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