Question

Tilly the dog barks every 9 seconds.

Answer 1

For this question you need to find the Lowest Common Multiple (LCM) of 9 and 12. We do this by finding the prime factorization of each number.
9 = 3 x 3
12 = 3 x 4
The LCM is found by multiply the highest number of each factor.
LCM = 3 x 3 x 4 = 36.

Answer 2

Aww... I have a dog named Tilly, *Ahem* It would take 36 seconds. Hope this helpz...