Q18: Departments A, B, and C have 10 employees each, and department D has 20 employees.Departments A, B, C, and D have no employees in common. A task force is to be formed by selecting 1 employee from each of departments A, B, and C and 2 employees from department D. How many different task forces are possible? A. 19,000 B. 40,000 C. 100,000 D. 190,000 E. 400,000
答案是D,请问怎么做的啊?
3x! |