Assume the Daily Consumption of Electric Power (In Millions of Kilowatt-Hours)

Essay

Assume the daily consumption of electric power (in millions of kilowatt-hours) of a certain city
has the probability density $p ( x ) = \left\{ \begin{array} { l l } \frac { 1 } { 9 } x e ^ { - \frac { x } { 3 } } & \text { if } x \geq 0 \\0 & \text { if } x < 0\end{array} \right.$ If the city's power plant has a daily capacity of 12 million kilowatt-hours, what is the probability that the available power supply will be inadequate on any given day?