# Is there a way to calculate the probability of drawing X+ > y% of time given X- [closed]

Say I have a bag with 10 balls (either red or blue), and I know that there are 8 balls that are red. How do I calculate the probability of drawing a a red ball $>75\%$ of the time if the first ball I picked without replacements is red? Hope this is clear. Thanks!

## closed as unclear what you're asking by whuber♦Feb 24 '14 at 20:50

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• To what "time" do you refer? Does the 75% include the first ball you drew? Do you mean you know exactly eight balls are red or that you know there exist eight red balls in the bag? – whuber Feb 24 '14 at 20:09
• thanks your question was enough to answer my original question. I was not thinking straight by not defining time correctly. – Ahdee Feb 24 '14 at 20:18