A box contains identical balls in three different colors - Black, white and blue. There are 8-x blue balls and 2X+5 black balls. If a ball is picked at random from the box, what is the probability that the ball is either blue or black?
1) X=2
2) There are 3X+39 white balls in the box.
OA is [spoiler](B)[/spoiler]
Please explain!!!
Can we expect such extra-ordinary questions in GMAT
Probability!!!
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- ronnie1985
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P(ball is blue or black) = P(blue) + P(black) = (blue balls)/(Total balls) + (black balls)/(Total balls)ronnie1985 wrote:A box contains identical balls in three different colors - Black, white and blue. There are 8-x blue balls and 2X+5 black balls. If a ball is picked at random from the box, what is the probability that the ball is either blue or black?
1) X=2
2) There are 3X+39 white balls in the box.
OA is [spoiler](B)[/spoiler]
Statement(1):
Let 'W' be the white-coloured balls, then
Total balls = (8 - x) + (2x + 5) + W = 13 + x + W
P(blue) + P(black) = (8 - x)/(13 + x + W) + (2x + 5)/(13 + x + W)
x and W are not known.
INSUFFICIENT
Statement(2):
Total Balls = (8 - x) + (2x + 5) + (3x + 39) = 4x + 52
P(blue) + P(black) = (8 - x)/(4x + 52) + (2x + 5)/(4x + 52) = (x + 13)/(4x + 52) = 1/4
SUFFICIENT
[spoiler](B)[/spoiler] is the answer.
So, was there anything 'extraordinary' about it?
Aneesh Bangia
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Well only solving this particular question would have actually given us a perfectly good answer in the form of B.
If you do not solve the question and from above if you treat this question as if the total is not given, so C should be the answer choice, then you would get the answer as incorrect.
GMAT has this habit of confusing between options C and E and also between C and any of the given options i.e A or B>
Hence the correct answer is B. Be careful...
If you do not solve the question and from above if you treat this question as if the total is not given, so C should be the answer choice, then you would get the answer as incorrect.
GMAT has this habit of confusing between options C and E and also between C and any of the given options i.e A or B>
Hence the correct answer is B. Be careful...
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LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!
Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.