Answer:
[tex]V = 25d ^ 3 + 275d ^ 2 + 250d[/tex]
Step-by-step explanation:
If the pool has a rectangular shape then its volume can be written as:
V = Width * Length * Depth
Let's call:
w = width
l = length
d = depth.
So we know from the statement of the problem that:
[tex]d = d[/tex]
[tex]w = 5 + 5d[/tex] (5 feet more than 5 times the depth)
[tex]l = 50 + 5d[/tex] (50 feet more than 5 times the depth)
Then, the volume can be written according to the depth as:
[tex]V = d(5 + 5d)(50 + 5d)[/tex]
[tex]V = d[250 + 25d + 250d + 25d ^ 2][/tex]
[tex]V = 25d ^ 3 + 275d ^ 2 + 250d[/tex]