Posted by **George** on Monday, January 14, 2013 at 5:14pm.

The supply office for a large construction firm has three welding units of Brand A and three welding units that are not Brand A in stock. If a welding unit is requested, the probability is .7 that the request will be for Brand A. Find the probability that exactly one of the non-brands A units will be left immediately after the third Brand A is requested.