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A box contains 10 balls, which are either red or white in color
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05 Nov 2021, 23:27
05 Nov 2021, 23:27
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A
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E
Difficulty:
75%
(hard)
Question Stats:
57% (02:10) correct
43%
(02:14)
wrong
based on 244
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A box contains 10 balls, which are either red or white in color. If two balls are selected at random from the box, what is the probability that the both the selected balls are white?
(1) The probability that one red ball and one white ball is selected is 16/45
(2) The probability that both the selected balls are red is 28/45
(1) The probability that one red ball and one white ball is selected is 16/45
(2) The probability that both the selected balls are red is 28/45
Similar question: https://gmatclub.com/forum/a-box-contai ... 99940.html
Re: A box contains 10 balls, which are either red or white in color
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06 Nov 2021, 00:36
06 Nov 2021, 00:36
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Expert Reply
Roy867 wrote:
A box contains 10 balls, which are either red or white in color. If two balls are selected at random from the box, what is the probability that the both the selected balls are white?
(1) The probability that one red ball and one white ball is selected is 16/45
(2) The probability that both the selected balls are red is 28/45
(1) The probability that one red ball and one white ball is selected is 16/45
(2) The probability that both the selected balls are red is 28/45
We are looking for \(\frac{w}{10}*\frac{w-1}{9}\).
Thus, we require value of w.
(1) The probability that one red ball and one white ball is selected is 16/45
\(\frac{w}{10}*\frac{r}{9}*2C1=\frac{16}{45}\)
(2) The probability that both the selected balls are red is 28/45
\(\frac{r}{10}*\frac{r-1}{9}=\frac{28}{45}.........r(r-1)=28*2=56=8*7\), so r=8, making w=2.
Suff
B
Re: A box contains 10 balls, which are either red or white in color
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12 Jul 2023, 06:09
12 Jul 2023, 06:09
r=10-w
So option a can also be correct as probability can be calculated from the same
Posted from my mobile device
So option a can also be correct as probability can be calculated from the same
Posted from my mobile device
