A box contains 6 black balls and 4 white balls. If two balls are selected at random without replacement, what is the probability that both balls are white?
A. 7/90
B. 3/25
C. 2/15
D. 4/25
E. 4/9
Answer: C
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A box contains 6 black balls and 4 white balls. If two balls are selected at random without replacement, what is the pro
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A box contains 6 black balls and 4 white balls. If two balls are selected at random without replacement, what is the probability that both balls are white?
Number of ways of selecting 2 white balls from 4 white balls without replacement = 4C2 = 6 ways
Number of ways of selecting 2 balls from a box, which contains 6 black balls and 4 white balls, without replacement = 10C2 = 45 ways
Probability that both balls are white = 6/45 = 2/15
Choice C is the answer.
Number of ways of selecting 2 white balls from 4 white balls without replacement = 4C2 = 6 ways
Number of ways of selecting 2 balls from a box, which contains 6 black balls and 4 white balls, without replacement = 10C2 = 45 ways
Probability that both balls are white = 6/45 = 2/15
Choice C is the answer.
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Solution:
There are 10 balls in the box. The probability that the first ball drawn will be white is 4/10, and the probability that the second ball will also be white is 3/9. Thus, the probability of selecting two white balls, without replacement, is 4/10 x 3/9 = 2/5 x 1/3 = 2/15.
Answer: C
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