Answer:
A. 1.04 m/s
B. 0
C. 1.72 m/s
Step-by-step explanation:
A. Displacement by Mamba in 2.50 s moving with the velocity 18 km/h (= 5 m/s) is
D = v t
D = (5 m/s) (2.5 s) = 12.5 m
On the return journey to the hideout, Mamba will cover the same displacement in 12.0 s. Thus, average velocity during it's return journey is

B. For the complete trip, since initial and final position are same, the total displacement is zero, the average velocity for the round trip would be zero.
C. Average speed of the complete trip can be calculated by dividing the total distance by total time taken.
Total distance = 12.5+12.5 = 25 m.
Total time taken = 12 +2.5 = 14.5 s
Therefore, average speed of the complete trip of mamba is (25 m) /(14.5 s) = 1.72 m/s.