Answer:
20 feet below sea level
Step-by-step explanation:
Answer:
the rate of change of the water depth when the water depth is 10 ft is; 
Step-by-step explanation:
Given that:
the inverted conical water tank with a height of 20 ft and a radius of 8 ft is drained through a hole in the vertex (bottom) at a rate of 4 ft^3/sec.
We are meant to find the rate of change of the water depth when the water depth is 10 ft.
The diagrammatic expression below clearly interprets the question.
From the image below, assuming h = the depth of the tank at a time t and r = radius of the cone shaped at a time t
Then the similar triangles ΔOCD and ΔOAB is as follows:
( similar triangle property)


h = 2.5r

The volume of the water in the tank is represented by the equation:



The rate of change of the water depth is :

Since the water is drained through a hole in the vertex (bottom) at a rate of 4 ft^3/sec
Then,

Therefore,

the rate of change of the water at depth h = 10 ft is:




Thus, the rate of change of the water depth when the water depth is 10 ft is; 
The parabola has a minimum value of -3 due to the subtraction at the end of the equation.
Answer:
You get 17.80 cents back
Step-by-step explanation:
4.5 times 0.49 is 2.20 cents
20 minus 2.20 is 17.80 dollars
Let's remember the equation for the volume of a cube:
V= x^3 where x is the length of one side
Since a cube has equal length for length, width, and height.
Now, use what you're given
V= 1331
And put that in terms of x
x^3 = 1331
Now solve for x!
x= cube root (1331)
Think about it! cube root of 1331 * cube root of 1331 * cube root of 1331... will equal 1331 m^3!
Hope this helps