The Probabilities That the Life of a Machine Will Vary

Multiple Choice

The probabilities that the life of a machine will vary from 6 to 12 years are given in the table below. The expected life of the machine is ____________.
$$\begin{array} { | l | l | l | l | l | l | l | l | l | } \hline \text { Life, Years } & 5 & 6 & 7 & 8 & 9 & 10 & 11 & 12 \\\hline \text { Probability } & 0.10 & 0.15 & 0.2 & 0.15 & 0.20 & 0.10 & 0.05 & 0.05 \\\hline\end{array}$$

A) 8.70 years
B) 9 years
C) 10.15 years
D) 7.95