Using the Impulse Theorem, we have:
[tex]F_{r}.\Delta t=m.\Delta v \\ (F-F_{at}).(3-0)= \frac{P}{g} .(v-0) \\ (90-100.0,25).3= \frac{100v}{10} \\ v= \frac{3.65}{10} \\ \boxed {v=19,5 m/s}[/tex]
If you notice any mistake in English, please let me know, because I'm not native.