A lot contains 40 articles.The probability that the lot contains exactly 4 defective articles is 0.7 and the probability that it conatins exactly 5 defective articles is 0.3. Articles are drawn at random from the lot one by one without replacement and are tested till all the defective articles are found. Find the probability that the testing procedure ends at tenth test.

Debjit Dutta , 13 Years ago

Grade 12