You have 3 jars. Each jar has a label on it: white, black,
or white&black. You have 3 sets of marbles: white, black,
and white&black. One set is stored in one jar. The labels
on the jars are guaranteed to be incorrect (i.e. white will
not contain white). Which jar would you choose from to give
you the best chances of identifying the which set of
marbles in is in which jar?
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Answer / md abdul aziz
there will be 2 combinations of the incorrect labeling.
lets suppose A,B,C are three jars and A has white, B has
Black and C has both of them.
now possible labeling will be A:B; B:B&W; C:W or A:B&W; B:W,
C:B . There cannot be other combinations...try it.
now in either of cases you choose the jar labeled with B&W
i.e mixture. and see which color of marbles are there. It
wont have both as it is incorrectly labeled. So it will be
the jar of such type of marbles and the remaining jars can
be easily identified with the justification of incorrect
labeles.
| Is This Answer Correct ? | 24 Yes | 8 No |
Answer / dv
It doesn't matter, pick any jar:
Jar: B W B&W
#1 w b&w b
#2 b&w b w
| Is This Answer Correct ? | 30 Yes | 14 No |
Answer / loz
The answer is the black and white jar.
The three jars do not have 3 different colors in. Lets say
Jar 1 has 100 white marbles. Jar 2 has 100 black marbles.
Jar 3 has 50 white marbles and 50 black marbles in. You
can say, confusingly, that Jar 3 has 100 black & white
marbles in.
The '&' causes the confusion and makes you think it's a
multi-colored marble. Once you realise it's not the answer
is simple.
Only two possible arrangements are possible.
Jar Arrangements: B W B&W
Arrangement #1 w b&w b
Arrangement #2 b&w b w
If you pick from the jar labelled B you might pick out a
white marble and either arrangement can be true. If you
pick from the jar labelled W you might pick out a black
marble and again either arrangement can be true.
Only the jar labelled B&W can give you a definitive answer.
| Is This Answer Correct ? | 10 Yes | 2 No |
Answer / hannes
I will choose black&white
White does not contain white:
B or B&W
there is a 50% chance to have a white marble
Black does not contain black
W or B&W
there is a 50% chance to have a blackmarble
B&W contains eather black or white
there is a 100% chance to have either a white or black
marble
| Is This Answer Correct ? | 6 Yes | 2 No |
Answer / sceptic
DV is ABSOLUTELY Right. There is only and only 2 combination
possible for this problem. Even if you try you cannot
arrange them in any other way. So,
Jar Arrangements: B W B&W
Arrangement #1 w b&w b
Arrangement #2 b&w b w
So you pick any Jar and look at the color and it must follow
either Arrangement 1 or 2. So, you pick rest of your answer
from this table accordingly.
Scenario : Say you pick Jar:B and it contains White (w)
Color left: Black and B&W and Jar left: White and B&W
B&W cannot be in the B&W jar so it must be in the White Jar.
Exactly the same theory goes for whichever Jar you pick and
color it come out to.
**This is exactly what AJ said but I thought I would
reaffirm since people marked it as wrong :S
| Is This Answer Correct ? | 5 Yes | 4 No |
Answer / elx144
The white jar can be either black or white & black. The
black jar can be either white or black & white. The white &
black jar can be either black or white.
A white marble drawn from the black jar could be either
white or white & black.
A white marble drawn from the black & white jar means the
jar is white...
You must pick from the black & white jar first.
Once you know the mixed jar is white, you know the black jar
is either mixed or white; two jars can't be white at the
same time so the black jar is mixed and the white jar must
be black since there's no other options.
| Is This Answer Correct ? | 2 Yes | 1 No |
Answer / paresh
Many of them have answered correctly.
My answer is also -
Any Jar we select, we can be able to find out what all other jars has which color marble.
Don't just think, question is to confuse you. If you will try out then will come to know that any color jar u select u will get correct answer.
| Is This Answer Correct ? | 0 Yes | 3 No |
Answer / alex
Any BUT B&W.
By picking B you have probability of white equal to 75% (it is W or B&W = 100% * 50% + 50% * 50%).
By picking W you have probability of black equal to 75% (the same formula).
By picking B&W you have the same probability of picking black or white, so it is 50%.
So, if you pick B or W jar you have a higher probability of guessing which marble you will get out of it.
| Is This Answer Correct ? | 0 Yes | 3 No |
Answer / guest_328
Wells I actually have another explanation to the problem.
Below is just a list of all the things in the question,
list is not in any particular order!
Jars: W(white) | B(black) | W&B(multi-coloured)
-------------------------------------------------
Marbles: W(white) | B(black) | W&B(multi-coloured)
*Scenario 1 - chose Jar B
possibility of W=50%
possibility of W&B=50%
possibility of B=0%
*Scenario 2 - chose Jar W
possibility of W=0%
possibility of W&B=50%
possibility of B=50%
*Scenario 3 - chose Jar W&B
possibility of W=50%
possibility of W&B=0%
possibility of B=50%
Therefore, based on the results above and the fact that all
labels on the jars are guaranteed to be wrong...
To identify W-marbles, can only choose
*Jar B or W&B
To identify B-marbles, can only choose
*Jar W or W&B
To identify W&B-marbles, can only choose
*Jar B or W.
| Is This Answer Correct ? | 3 Yes | 7 No |
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