Assuming the traveling speed to be constant, the law that involves space, speed and time is
[tex] s = vt [/tex]
So, the sentence "Traveling at an average speed of 50 miles per hour, the trip from point A to point B takes 2 hours" translates to
[tex] s = 50\cdot 2 [/tex]
from which we deduce that A and B are 100 miles apart. In fact, we also have
[tex] s = 40\cdot 2.5 [/tex]
which again yields s = 100.
Now, the question changes the perspective, because it asks for the time needed to travel at a certain speed. Now that we know that the distance is 100 miles, if we travel at 45 miles per hour we have
[tex] 100 = 45t [/tex]
from which we can deduce
[tex] t = \cfrac{100}{45} = 2.\overline{2} [/tex]
which, rounded to the nearest hundreth, is 2.22.
