the probability of drawing $4$ white balls from an urn containing $10$ White ball , $4$ black and $3$ red balls ?

I have tried to use probability formula which is not working here

  • $\begingroup$ The problem as stated is vague. Draw with or without replacement? $\endgroup$ – Ron Gordon Jul 8 '13 at 13:40
  • $\begingroup$ yeah that what i am not understanding ! $\endgroup$ – SSK Jul 8 '13 at 13:41
  • $\begingroup$ and in how many draws? $\endgroup$ – mm-aops Jul 8 '13 at 13:44
  • 2
    $\begingroup$ Can you type the full question here, word to word? $\endgroup$ – dotslash Jul 8 '13 at 13:44
  • $\begingroup$ yea i have typed word to word :) $\endgroup$ – SSK Jul 8 '13 at 14:02

What's really not clear, is how many time you draw balls. I assume you do it 4 times, so the question breaks down into 2 cases:

Case 1 (with replacement): the successful outcome is to have $4$ successes out of $4$ trials, and the probability is fixed: $\big(\frac{10}{17}\big)^4$

Case 2 (without replacement): same, but the number of white and total balls reduces after each sample: $\frac{10}{17} \cdot \frac{9}{16} \cdot \frac{8}{15} \cdot \frac{7}{14}$


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