As shown in the figure, a source of sound moves along the X-axis at...

The sound is emitted when the source crosses the origin $P$. According to the given information, the source is at $P$ at time $t = 0$.

The distance between the origin $P$ and the listener $Q$ is $d = 330 \text{ m}$.

The speed of sound in air is $v = 330 \text{ m s}^{-1}$. Note that the speed of sound in a medium is independent of the speed of the source.

The time taken for the sound to travel from $P$ to $Q$ is given by:
$t = \dfrac{\text{Distance}}{\text{Speed of sound}}$

$t = \dfrac{330 \text{ m}}{330 \text{ m s}^{-1}} = 1 \text{ s}$

Since the sound was emitted at $t = 0$, it reaches the listener $Q$ at $t = 1 \text{ s}$.