45 : 5 : 3 * 9 =

Let's solve this step by step:

1. First, we divide 45 by 5: $$45 : 5 = 9$$.
2. Then, we divide the result by 3: $$9 : 3 = 3$$.
3. Finally, we multiply the result by 9: $$3 \cdot 9 = 27$$.

Answer: 27