Since the equation is already given, as well as the average speed of both the bus and her walk, we can just simply solve for x, which is the time.
40(0.9-x) = 5x
36-40x = 5x
36 = 5x + 40x
36 = 45x < divide both sides by 45 so the result would be:
x = 0.8
Therefore, it took Talia 0.8 hour to walk home or 48 minutes.
Please correct me if I'm wrong!! :)