ANSWER
The different ways of ranking the teams is 455 ways
EXPLANATION
Given that;
Note, that any team can be rank first, second, and third
Therefore, we can apply combination to find the number of ways
[tex]\begin{gathered} \text{ }^{15}\text{C}_3\text{ = }\frac{\text{ 15!}}{(15-3)!\text{ 3!}} \\ \\ \text{ }^{15}\text{C}_3\text{ = }\frac{\text{ 15!}}{12!3!} \\ \\ \text{ }^{15}\text{C}_3\text{ = }\frac{\text{ 15 }\times\text{ 14 }\times\text{ 13}}{6} \\ \\ \text{ }^{15}\text{C}_3\text{ = }\frac{\text{ 2730 }}{\text{ 6}} \\ \text{ }^{15}\text{C}_3\text{ = 445 ways} \end{gathered}[/tex]Therefore, the different ways of ranking the teams is 455 ways