2.42. The areas of the bases of a truncated pyramid are $S_{1}$ and $S_{2}$ $\left(S_{1}<S_{2}\right)$, and its volume is $V$. Determine the volume of the complete pyramid.
2.42. Instruction. Use the equality $\frac{S_{1}}{S_{2}}=\frac{x^{2}}{H^{2}}$, where $\boldsymbol{x}=\boldsymbol{H}-\boldsymbol{h}(\boldsymbol{H}-$ the height of the full pyramid, and $h$ - the height of the truncated pyramid).

Answer: $\frac{V S_{2} \sqrt{S_{2}}}{S_{2} \sqrt{S_{2}}-S_{1} \sqrt{S_{1}}}$.