How far is a wall that echoes back a word of $m=5$ syllables $n=3$ seconds after it is spoken? A person can speak two syllables per second. The speed of sound is $V=340 \frac{\mathrm{m}}{\mathrm{sec}}$.
$$
x \equiv \frac{1}{2} V\left(\frac{m}{2}+n\right)=935 \text{ m}
$$