GREETINGS!
Answer is 553 m/s
By the formula of,
  Vf = Vi + at 
 where,
 Vi is initial velocity
 a is acceleration due to gravity
 t is time.
As we know that,
 F = ma
 so, 
 

put this in the final velocity formula,
 Vf = Vi + (F/m)t
 Vf = 125 + (25000/440)7.5
 Vf = 551.13 m/s
HOPE IT HELPS!