Two fighter jets are flying towards each other. Jet A, with a mass of 15000 Kg, is traveling to the right with a speed of 255 m/s, whereas Jet B, with a mass of 34000 kg, is traveling to the left at 145 m/s. If the collision is perfectly inelastic, determine the final velocity of the jets.
This is a ridiculous question. If two jets collide head-on, they will be both break up. They will not stick together.
They probably want you to use conservation of momentum, which will tell you the speed of the center of mass of the resulting fragments.