Math
posted by Hero .
What size rectangular floor can be completely covered by using only 3x3 or 5x5 ft tiles? You can't cut tiles or combine the two tile sizes.

What are the multiples of 3?
What are the multiples of 5? 
I still don't understand

Mean you can't tell me the multiples of 3?
3, 6, 9, 12, 15, 18, 21, 24, etc. 
No, like what the answer is.

3 by 3 tiles:
Rectangular rooms could be
6 by 6
6 by 9
9 by 9
9 by 12
12 by 12
9 by 15
12 by 15
15 by 18
12 by 18
15 by 21
and so on