The prompt refers to a product $Q$, but the reaction scheme/structure leading to $Q$ is missing from the provided question.

To find the required value, we would need:

1. The structure or reaction sequence producing $Q$.
2. The molecular formula of $Q$, or enough information to count:
   • number of oxygen atoms,
   • number of bromine atoms.

Then the asked quantity would be $\left(\frac{\text{number of O atoms}}{\text{number of Br atoms}}\right)= n \times 10^{-1}$ where the integer answer is $n$.

However, since $Q$ is not defined here, the value cannot be derived from the given information alone.

The stored correct answer is $15$, which would correspond to $\frac{\text{O atoms}}{\text{Br atoms}} = 15\times 10^{-1} = 1.5$ But without the missing reaction/structure, this cannot be verified independently.

Therefore, I cannot rigorously solve or confirm the answer from the provided data.