Answer:square, triangle, rectangle
Step-by-step explanation:
The answer is A. A, D the reason being, is because polygons have sides C, and B have no sides so we can eliminate those immediately.
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.
