A mixed ether ${ }^{(P)}$, when heated with excess of hot concentrated hydrogen iodide produces two different alkyl iodides which when treated with aq. NaOH give compounds $(\mathrm{Q})$ and $(\mathrm{R})$. Both $(\mathrm{Q})$ and ${ }^{(R)}$ give yellow precipitate with NaOI . Identify the mixed ether ${ }^{(P)}$ :