The values of \( Q \) at \( t = 6 \) are approximately:
- For the increasing function: \( Q \approx 45.398 \)
- For the decreasing function: \( Q \approx 14.397 \)
Thus, the final answers are:
\[
\boxed{Q_{\text{increase}} \approx 45.398}
\]
\[
\boxed{Q_{\text{decrease}} \approx 14.397}
\]