Answer:
[tex]v = 8.333\,\frac{m}{s}[/tex]
Explanation:
The system mosquito-raindrop is described by the Principle of Momentum Conservation:
[tex](50\cdot m)\cdot (8.5\,\frac{m}{s})+m\cdot (0\,\frac{m}{s} ) = 51\cdot m \cdot v[/tex]
[tex]425 = 51\cdot v[/tex]
The final speed is:
[tex]v = 8.333\,\frac{m}{s}[/tex]