Posted by **TA** on Sunday, May 6, 2012 at 8:35pm.

A cellular phone manufacturer randomly selects 5 phones from every batch of 50 produced. If at least one of the phones is found to be defective than each phone in the batch is tested individually. Find the probability that the entire batch will need testing if the batch contains

a). 8 defective phones

b). 2 defective phones