The relative rate of acid catalysed dehydration of following alcohols would be:

IV

Major product of the given reaction is: 

In the given reaction $\left[\mathrm{X}\right]$ and $\left[\mathrm{Y}\right]$ will be:

${\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{O}-{\mathrm{CH}}_3\stackrel{\mathrm{HCl} \left(1\mathrm{eq}\right)}{\to }\left[\mathrm{X}\right]+\left[\mathrm{Y}\right]$

What are $\left(\mathrm{P}\right), \left(\mathrm{Q}\right)$  respectively in the above reaction ?