Explanation:
Given:
D(t) models the distance Alek walked (in kilometers) after t hours.
⟹D(0.5)⟹D(0.5) is the distance Alek walked after 0.5 hours.
Similarly, D(1)D(1) is the distance Alek walked after 1 hours.
⟹D(1)−D(0.5)⟹D(1)−D(0.5) is the distance covered by Alek between time t = 0.5 hour and 1 hour.
So, D(0.5)<D(1)−D(0.5)D(0.5)<D(1)−D(0.5) means the distance by Alek in first 0.5 hours is less than the distance covered by Alek in the next 0.5 hours.