Answer:
9
Step-by-step explanation:
LCM is the smallest multiple what is common to all the numbers.
[tex]45 = {3}^{2} \times 5 [/tex]
[tex]15 = 3 \times 5[/tex]
For LCM to be 45,
[tex]n = {3}^{2} \\ = 9[/tex]
