Which of the following could represent the scale factor of the larger figure to the smaller figure?

Two cylinders are shown and one is larger than the other. The height of the larger cylinder is 30 meters. The diameter of the larger cylinder is 18 meters. The height of the smaller cylinder is 20 meters. The diameter of the smaller cylinder is 12 meters.
There is 2 answers to this problem!
15:9
5:3
3:2
21:14
2:3
20:30

5:3 and 3:2 are both possible scale factors for the larger figure to the smaller figure.