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A bag contains only 3 different colours and atleast one ball of red

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A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post Updated on: 13 Feb 2017, 18:33
2
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A
B
C
D
E

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  75% (hard)

Question Stats:

47% (01:10) correct 53% (01:06) wrong based on 117 sessions

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A bag contains only 3 different colours and atleast one ball of red, white and blue colour. If the number of balls of each colour is distinct and red coloured balls are more than each of the other two colours, what is the probability of picking red ball?

(1) number of blue and white ball is half of total number of ball.
(2) there are 3 red coloured balls.

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1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


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Originally posted by chetan2u on 13 Feb 2017, 04:46.
Last edited by chetan2u on 13 Feb 2017, 18:33, edited 2 times in total.
Renamed the topic.
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Re: A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post 13 Feb 2017, 08:18
I think its A
(1) P picking red ball = 1/2
(2) no info about total ball number
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Re: A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post 13 Feb 2017, 09:52
Hi,

I think it's D.

For statement 2:
Though the total number of balls was not mentioned, We can estimate the number of blue and white balls from the condition given in the question "the number of balls of each colour is distinct and red coloured balls are more than each of the other two colours".

So, the only possibility is that the number of blue and white colour balls are 2 and 1.

Then the probability of selecting a red ball is again 1/2.

Please post OA.
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Re: A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post 13 Feb 2017, 10:06
chetan2u wrote:
A bag contains only 3 different colours and atleast one ball of red, white and blue colour. If the number of balls of each colour is distinct and red coloured balls are more than each of the other two colours, what is the probability of picking red ball?

(1) number of blue and white ball is half of total number of ball.
(2) there are 3 red coloured balls.


Hi,

rephrase the stem question to R/(R+W+B) ?

1. it says W+B=(W+B+R)/2 ---> W+B=R put it back in above equetion and it gives 1/2. sufficient
2. if there are 3 red balls and in stem it says the number of balls differ, there are more reds than other two and at least 1 of each exist then either w=1,B=2 or b=1,w=2. therefore sufficient.

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Re: A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post 13 Feb 2017, 18:38
2
trangphamthuy91 wrote:
I think its A
(1) P picking red ball = 1/2
(2) no info about total ball number


Hi
Relook in the statement II..
Red ball are 3, buy the other info is..
1) red is max and ATLEAST one of each colour
2) all three are distinct number..

So clearly red is 3 and other 2 are 1 and 2..
Now we can find probability
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


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Re: A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post 14 Feb 2017, 01:44
chetan2u wrote:
A bag contains only 3 different colours and atleast one ball of red, white and blue colour. If the number of balls of each colour is distinct and red coloured balls are more than each of the other two colours, what is the probability of picking red ball?

(1) number of blue and white ball is half of total number of ball.
(2) there are 3 red coloured balls.



D ..

A .(B+W) = 1/2x , R = 1/2x
p = 1/2
suff

B.Given red = 3 .. and in the question stem it is mentioned that number of each color is distinct and the bag have atlst one ball of each color ...so the possible value of red and blue will be 2,1 or 1,2
so p = 3/6 =1/2..
suff

So D.
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A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post 19 Feb 2017, 00:35
R>W and R>B

1) B+W= B+W+R/2 => 2B+2W=B+W+R => B+W=R
Probability of picking Red is R/B+W+R => R/R+R =R/2R Sufficient
2) R=3; So, W and B could be 1,2 or 2,1 => probability is 3/3+2+1 Sufficient
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Re: A bag contains only 3 different colours and atleast one ball of red  [#permalink]

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New post 25 Oct 2018, 21:49
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Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: A bag contains only 3 different colours and atleast one ball of red &nbs [#permalink] 25 Oct 2018, 21:49
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