A company is building 100 new apartments. Based on previous data from similar areas, the company knows that the propability is 25% that a household will not have a car, 50% that a household will have 1 car and 25% that a household will have 2 cars. How many parking spaces should the company build if the company wants to be 95% sure that all cars in every household can be parked? (number of parking spaces must be equal to or greater than the number of the total number of cars)
I truly do not know how to proceed. Really greatful for help.
I was thinking of using a binomial distribution, but since there are three different outcomes, I do not know what to do. I suppose I could divide the binomial distribution into "0 cars" vs "1 car or more" but I don't understand where to go from there.
I suppose I could enter all values into Excel and calculate every possible combination of cars that can exist but that feels like a bad method.