Hey! can someone give me a step-by-step explanation on how to solve this problem correctly? I know for a fact that I did it incorrectly.

Answer:
B. 1:18
Explanation Down Below
Step-by-step explanation:
Hello!
First, let's find the volume of each cylinder by plugging in the given values.
Volume of a Cylinder: [tex]V = \pi r^2h[/tex]
Since the variables are the same as given in the formula, we can just use the formula as the volume.
[tex]\implies{\boxed{{V = \pi r^2h}}[/tex]
We have to plug in 3r for the radius, and 2h for the height.
[tex]\implies \boxed{ V = 18\pi r^2h}[/tex]
We can see that the Volume of Cylinder B is just 18 times the Volume of Cylinder A, but we can find the same ratio using equations.
The answer is Option B. 1:18.