The Density Function for the Life of a Certain Type $p ( t ) = 0.2 e ^ { - 0.2 t } , t > 0$

Short Answer

The density function for the life of a certain type of battery is modeled by $p ( t ) = 0.2 e ^ { - 0.2 t } , t > 0$ and is measured in months.(a) What is the probability that a battery will wear out during the first month of use?
(b) What is the probability that a battery is functioning for more than 12 months?