Suppose we modify the production model to obtain the following mathematical model:
```
Max 13x
s.t.
ax}\begin{array}{c}{ax42}\\{x}
```
where \( a \) is the number of hours of production time required for each unit produced.
With \( a=5 \), the optimal solution is \( x=8.4 \).
If we have a stochastic model with \( a=3, a=4, a=5 \), or \( a=6 \) as the possible values for the number of hours required per unit, what is the optimal value for \( x \) ? (Round your answers to two decimal places. Let \( P \) be total profit.)
(a) \( a=3 \)
\[
\begin{array}{l}
x=\square \\
P=\square
\end{array}
\]
(b) \( a=4 \)
\[
\begin{array}{l}
x=\square \\
P=\square
\end{array}
\]
(c)
\[
\begin{array}{l}
a=5 \\
x=8.4 \\
P=\square
\end{array}
\]
(d)
\[
\begin{array}{l}
a=6 \\
x=\square \\
P=\square
\end{array}
\]
(e) What problems does this stochastic model cause?
Since the value of \( a \) is -- Select \( -\vee \), the values of \( x \) and profit - Select \( -\cdots \) known with certainty.