The answer is one solution I think
So hmm check the picture below

a)
well, clearly is 80 ft/s
b)
when t = 1? well 80(1)
c)
in the picture, x-axis is the time and y-axis is the height
so, it reaches its maximum at the vertex, after "x" seconds

so it reached the vertex after

d)
the maximum height of the ball is
Answer:
Mean= $ 1.96
Mode= No mode
Step-by-step explanation:
Mean is the value obtained by dividing the sum of all the observations by their numbers.
Mean is obtained by dividing the total number of the values with the number of values.
Mean= x1+ x2+ x3 + x4/ 4
Mean = $ 1.5 + $ 2.0 + $ 2.15 + $ 2.20/4= 7.85/4= 1.9625or 1.963 or $ 1.96
Mode is the most frequent occurring value in a data set. But since all the values in the given set occur only once the data does not have any mode .
There is no mode because every value has the same frequency, that is it occurs the same number of times.