Hello, Need help with a problem

Hey, im making a 2D game which player has to dodge objects that fall from sky in it. now what i want is an object that gets spawned randomly between two points of time, stay in the game for a period of time then gets destroyed... for instance:

game starts -> unity chooses a number between 1-10 -> number is 7 -> unity spawns my objects after waiting for 7 seconds ->object is in the game for 2seconds then objects gets destroyed-> after object was destroyed unity again chooses a number between 1-10 -> this time its 6 -> unity spawns my object -> etc.

Thank you, sry for bad English.