There are 30 cars in my building's parking lot. All of the cars are red or white, and a car can have either 2 doors or 4 doors. of them are red, of them are 4-door, and 8 of them are 2-door and white. How many of the cars are 4-door and red?
I think you are missing some of your question!
See the answer here: https://web2.0calc.com/questions/question_21657#r1