Velocity=Distance travelled/ time taken
V=D/T
Thus, T=D/V

Given, V(truck)=45 mph
V(car)=60 mph.
Assume they both travel D miles of distance.

Say, the Truck takes X hours to finish the distance of D miles.
Then X = D/45
(Hrs = Miles / Miles/Hr)

Also, say the car takes Y hours to travel the same distance D.
Then Y= D/60
Then Y (hrs) = D (miles)/ 60 MPH

We also know the truck travels 2 hrs longer.
Thus X=Y+2

Putting all together,

D/45= (D/60)+2

or,
(4D-3D)/180 = 2
Thus D=360 miles.

Then the truck travelled, X hrs = D/45 = 360/45 = 8 hrs.

And the car travelled,
Y=D/60 = 360/60=6 hrs.