SOLUTION: An IRS auditor randomly selects 3 tax returns from 57 returns of which 8 contain errors. What is the probability that she selects none of those containing errors?

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Question 1060894: An IRS auditor randomly selects 3 tax returns from 57 returns of which 8 contain errors. What is the probability that she selects none of those containing errors?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
There are 57-8=49 returns with no errors.
There are 57%2A56%2A55%2F%281%2A2%2A3%29 possible sets of 3 returns that the auditor could pick.
Of those 49%2A48%2A47%2F%281%2A2%2A3%29 are sets of 3 returns with no errors.
The number of possible sets of 3 returns with no errors,
as a fraction of the number of possible sets of 3 returns available for auditing is
49%2A48%2A47%2F%2857%2A56%2A55%29=about+0.630 ,
so the probability that the auditor selects none of the return containing errors is about highlight%280.630=%2263.0%22%2F100=%2263.0%25%22%29 .