A new batterys voltage may be acceptable (A) or unacceptable (U). A certain flashlight requires two batteries,

Question:

A new battery’s voltage may be acceptable (A) or unacceptable (U). A certain flashlight requires two batteries, so batteries will be independently selected and tested until two acceptable ones have been found. Suppose that 80% of all batteries have acceptable voltages, and let y denote the number of batteries that must be tested.
a. What are the possible values of y?
b. What is p (2), that is, P(y = 2)?
c. What is p (3)?