A street has 30 street lights in a row. If 8 of the street lights are damage and you are going to replace them and don't know which of the lights are damage.
1. What is the probability that you chosen exactly the 8 damage lights and all 30 lights are working?
2. In how many combinations you can choose all 8 lights and you didn't replace the damage lights?
3. In how many combinations you can choose all 8 lights and 3 of the lights are still damage?