Distance = rate*time, or
distance = (average speed)* time, so
average speed = distance/ time.
average speed = 205 mi / (3/12) h = 205 mi/ (1/4)h = 205*4 mi/h=
= 820 mi/h
It is looks to high for speed of the truck,
probably time should be 3.12 h,
then
average speed = 205 mi / (3.12) h ≈ 65.71 mi/h.
That looks close to real life.