jmc

Let the sides of the prism have lengths $x$, $y$, and $z$. We have the equations $xy=15$, $yz=10$ and $xz=6$. Multiplying these equations together, we have $xy\cdot yz\cdot xz=15\cdot 10\cdot 6\Rightarrow x^2{y}^2{z}^2=900$. Since the volume of the prism is equal to $xyz$, we take the square root of both sides to get the volume as $\sqrt{900}=\boxed{30}$ cubic inches.