First of all, I'm going to assume that we have a concave down parabola, because the stream of water is subjected to gravity.
If we need the vertex to be at
, the equation will contain a
term.
If we start with
we have a parabola, concave down, with vertex at
and a maximum of 0.
So, if we add 7, we will translate the function vertically up 7 units, so that the new maximum will be 
We have

Now we only have to fix the fact that this parabola doesn't land at
, because our parabola is too "narrow". We can work on that by multiplying the squared parenthesis by a certain coefficient: we want

such that:
Plugging these values gets us

As you can see in the attached figure, the parabola we get satisfies all the requests.
Irrational is the correct answer
Answer:
58.0
Step-by-step explanation:
Given the data:
56 65 62 53 68 58 65 52 56
Reorderd data: 52, 53, 56, 56, 58, 62, 65, 65, 68
Median = 1/2(n + 1) th term
n = sample size = 9
Hence,
Median = 1/2(9 + 1)th term
Median = 1/2(10)th term
Median = 5th term
5th term in the reordered data = 58
Hence, median age is 58