A Spacecraft with a total mass of 50,000kg is flying with a speed of 90m/s with respect to a distant planet. An internal explosion splits its front off, which is observed to drift away with a speed od 30m.s in the forward direction as observed in the reference frame of the remaining spacecraft. The remaining spacecraft has a mass of 32,000kg after the explosion. What is the speed of the remaining spacecraft with respect to the planet after the explosion?