Computer programs are classified by the length of the source code and by the execution time. Pro$-$ grams with more than $150$ lines in the source code are big $($B$).$ Programs with $<150$ lines are little $($L$).$ Fast programs $($F$)$ run in less than $0\mathrm{.}1$ sec$-$ onds. Slow programs $($W$)$ require at least $0\mathrm{.}1$ sec$-$ onds. Monitor a program executed by a computer. Observe the length of the source code and the run time. The probability model for this experiment contains the following information: P$[$LF$]=0\mathrm{.}5,$ P$[$BF$]=0\mathrm{.}2,$ and P$[$BW$]=0\mathrm{.}2.$ What is the sample space of the experiment? Calculate the fol$-$ lowing probabilities:

$($a$)$ P$[$W$]$

$($b$)$ P$[$B$]$

$($c$)$ P$[$WU B$]$