If a number is divisible by 3 and 5 then it is divisible by 15

Yes!

Step-by-step explanation:

Besides 15 and one, 3 and 5 are the greatest common factors of 15. Those numbers are therefore divisible by any product of 15.

Example:

45

45/3 = 15

45/5 = 9

45/15 = 3

Yes it is

Step-by-step explanation:

Since the multiplication of 3 and 5 will give 15

I. e 3 * 5 = 15

Then any number that can be divided by 3 and 5, can also be divided by 15.