Answer: The average speed is 3m/s.
Step-by-step explanation:
We can define the average speed as the quotient between the total distance traveled in a given period of time, and that period of time,
Here we have that:
d = distance
t = time.
"A lioness hunting antelope runs a distance of 60 m in 15 s"
1) d = 60m, t = 15s
"Then she stops to survey the herd for 20 s"
We add 0 meters to the distance, and 20 seconds to the time.
2) d = 60m + 0m, t = 15s + 20s = 35s
"she trots for 25 s over 60 m around the edge of the herd."
we add 60m to the distance, and 25s to the time
3) d = 60m + 60m = 120m, t = 35s + 25s = 60s.
"Finally, the lioness races after the antelope, traveling 120 m in 20 s"
we add 120m to the distance and 20s to the time.
4) d = 120m + 120m = 240m, t = 60s + 20s = 80s.
Then the average speed of the lioness in that period of time is:
S = 240m/80s = 3m/s
