The mass of gas emitted from the rear of toy rocket is initially 0.2 kg/sec. If the speed of the gas relative to the rocket is 40 m/sec and the mass of rocket is 4 kg. What is the acceleration of the rocket?​

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.