Probability Question

[rapidfire09]

Hi, Can somebody help me with following probability Question?

Thanks in advance


Nine marbles are numbered one through nine and placed in a jar. Three marbles are randomly selected from the jar, one is placed in a cup, and two are discarded. Next, another three marbles are selected from the jar, two are placed in the same cup as the first, and one is discarded. Finally, out of the three that remain in the jar, one is placed in the cup, and two are discarded. What is the probability that the four marbles in the cup all have prime numbers written on them?

It cannot be determined from the information given

[kamalchhabra]

Originally Posted by rapidfire09

Hi, Can somebody help me with following probability Question?

Thanks in advance


Nine marbles are numbered one through nine and placed in a jar. Three marbles are randomly selected from the jar, one is placed in a cup, and two are discarded. Next, another three marbles are selected from the jar, two are placed in the same cup as the first, and one is discarded. Finally, out of the three that remain in the jar, one is placed in the cup, and two are discarded. What is the probability that the four marbles in the cup all have prime numbers written on them?

It cannot be determined from the information given

the answer is the first option: 1/126
explanation: there is only one possibility of having all 4 primes in first 9 numbers...i.e. 2,3,5,7
and 4 marbles can be selected in 9C4 ways, i.e. 126...so the probability becomes 1/126

but when there is already a thread running for Probability questions, do you think its worth to open a new thread for just a single question?
kindly try and search for available threads before starting a new thread...

regards,
kamal

PS: moderators, please close this thread or add it to the existing one.