The BB-series of droids have spherical bodies and gyroscopic propulsion systems that allow them to roll across a variety of terrain.

The BB-series of droids have spherical bodies and gyroscopic propulsion systems that allow them to roll across a variety of terrain. Recently; however, the manufacturer has had several BB units returned because the propulsion system failed. In order to determine how pervasive this problem is, QA personnel randomly select 25 BB units and test their propulsion system. It is determined that 5 of the 25 BB units have defective systems. Based on this information, solve for the following probabilities.

1. If two BB units are selected at random, one at a time with replacement, what is the probability that both BB units have defective propulsion systems?
2. If three BB units are selected at, one at a time without replacement, what is the probability that all three have defective propulsion systems?