Rashed12 wrote:
Bunuel wrote:
There are 15 black chips and 5 white chips in a jar. What is the least number of chips we should pick to guarantee that we have 2 chips of the same color?
A. 19
B. 16
C. 6
D. 5
E. 3
Dear
Bunuel,
I am really confused about the above question. I have understood the below question and solution.
what is the difference between the two questions?the above question answer is 3, but my understanding is that answer is 16 when I am comparing this to the below solution.
kindly make me clear about the confusion.
The below solution form
GMAT CLUB TEST and it is your solution.
BELOW IS REVISED VERSION OF THIS QUESTION:
A box contains 10 tablets of medicine A and 15 tablets of medicine B. What is the least number of tablets that should be taken from the box to ensure that at least two tablets of each kind are among the extracted?
A. 12
B. 15
C. 17
D. 19
E. 21
The worst case scenario will be if we remove all 15 tablets of medicine B first. The next 2 tablets we remove have to be of medicine A, so to guarantee that at least two tablets of each kind will be taken we should remove minimum of 15+2=17 tablets.
Answer: C.
Bunuel wrote:
There are 15 black chips and 5 white chips in a jar. What is the least number of chips we should pick to guarantee that we have 2 chips of the same color?
A. 19
B. 16
C. 6
D. 5
E. 3
In this question, we want to ensure, to guarantee that we have 2 chips of the same color? So, we need to have tow white or two black chips. The worst case would be if for the first two pick we'll get one black and one white chips: BW or WB. The next (3rd) chip will be B or W in any case we'll have two chips of the same color: BW - W or BW - B.
Bunuel wrote:
A box contains 10 tablets of medicine A and 15 tablets of medicine B. What is the least number of tablets that should be taken from the box to ensure that at least two tablets of each kind are among the extracted?
A. 12
B. 15
C. 17
D. 19
E. 21
In this question, we want to ensure, to guarantee that we have at least two tablets of each kind are among the extracted. So, we need AABB. The worst case would be if we pick all 15 tablets of medicine B first: BBBBBBBBBBBBBBB. We will be left with 10 tablets of of medicine A. So, the next 2 tablets we remove have to be of medicine A, so we'd have
BBBBBBBBBBBBBBB
AA. This gives us at least two tablets of each kind.
Check other
Worst Case Scenario Questions from our
Special Questions Directory to understand the concept better.
Hope it helps.
_________________