#### Answer

$$w = \frac{3V}{lh}$$

#### Work Step by Step

To solve for $w$, we need to isolate $w$:
We first divide by $\frac{1}{3}$, which means we multiply by the inverse, which is $3$:
$$3V = lwh$$
To isolate $w$, divide both sides by $lh$ to get:
$$w = \frac{3V}{lh}$$