An IRS auditor randomly selects 3 tax returns from 55 returns of which 10 contain errors. What is the probability that she selects none of those containing errors?
A)0.5409
B)0.5477
C)0.0046
D)0.006

Question

Quizplus · Accepted Answer

The probability of selecting none of the returns containing errors can be calculated using combinations. There are 45 returns without errors out of 55. The number of ways to choose 3 returns from these 45 is 45C3. The total number of ways to choose any 3 returns from the 55 is 55C3. The probability is the ratio of these two combinations: (45C3) / (55C3) = 0.5409.

An IRS Auditor Randomly Selects 3 Tax Returns from 55