I keep getting the wrong answer

Answer: [tex]f(t)=550t[/tex]
Step-by-step explanation:
Given
Distance between Toronto to Dallas is 1200 miles
speed of the plane is 550 mph
We know, [tex]distance=speed\timestime[/tex]
for any time t, distance is given by
[tex]distance=f(t)=550\times t[/tex]
where t is hours
for [tex]t=0,f(t)=0[/tex] i.e. plane is at Dallas at 2 pm
time taken to reach dallas is [tex]\dfrac{1200}{550}=2.18\ \text{hr}[/tex]