Given data:
The expression for the distance traveled by the aircraft is D=400t.
The given time is t=6 hours.
Substitute 6 for t in the given expression.
[tex]\begin{gathered} D=400(6)\text{ miles} \\ =2400\text{ miles} \end{gathered}[/tex]Thus, the distane traveled by the aircraft in 6 hours is 2400 miles.