The mean is the average.
Let A = mean
A = (18 + 14 + 9 + 6 + 3)/5
A = 50/5
A = 10
Ellie's mean time is 10 seconds.
REVISED ANSWER.
In the picture, I have drawn on the example given. the RC and PD are the same because They are across from each other perfectly. So the answer is still PD=400m but if there can be two answers then I would have to say another possiblity would be 200m for the diameter of the pond. The wording of this problem is tricky and the picture can throw you off a bit but I did my best to answer properly here.
So if you could mark brainliest that would be awesome.
find the mean, median, and mode of the data set round to the nearest tenth 15, 1 , 4, 4, 8, 7, 15, 4, 5
Dmitriy789 [7]

<h3>Answer: mean = 7.5, median = 5, mode = 4</h3>
Answer: 2.26
Step-by-step explanation://Give thanks(and or Brainliest) if helpful (≧▽≦)//