4x + 13y = 40
4x + 3y = -40
multiply second equation by -1
4x + 13y = 40
-4x - 3y = 40
add equations together
10y = 80
y = 8
put y in either original equation
4x + 3(8) = -40
4x + 24 = -40
subtract 24 from both sides
4x = 64
x=16
y=8
The answer is: The diameter is 4 centimeters.
The explanation is shown below:
1. The volume of the cylinder is:

Where
is the radius (
) and
is the height (
).
Then:
2. The total volume of the 12 spheres is:

3. The volume of the cylinder and the total volume of all the 12 spheres, are equal, therefore:

4. Now, you must solve for the radius:
![r=\sqrt[3]{\frac{128\pi}{16\pi}}\\r=2cm](https://tex.z-dn.net/?f=r%3D%5Csqrt%5B3%5D%7B%5Cfrac%7B128%5Cpi%7D%7B16%5Cpi%7D%7D%5C%5Cr%3D2cm)
5. The diameter is:

23:8 is the simplest form. However, you can put 5.75:2 or even 2.86/1 if you are looking for the absolute simplest