The problem is:
1,2,3-trimethoxy-cyclohexane reacts with $x$ moles of $\ce{HI}$ to give $y$ moles of $\ce{CH3I}$ and iodo-cyclohexane as product. Then find the value of $\frac{x+1}{y+1}$.
I am not getting that how is iodohexane formed and also I am not able to think of any mechanism for this reaction.