題目：The 5-seater in the last row of a bus is empty and 3 passengers is ready to sit on it. In how many ways can the seats be arranged so that 2 adjacent seats are reserved?
求step and answer!
- polarbearhmhLv 45 年前最愛解答
We can consider the 2 adjacent seats (as the question required) to be "1 seat", so that the case equals to 3 passengers choosing 4 seats to sit.
The number of ways is then
(as the permutation of the 3 passengers counts as different ways)資料來源： The answer is 24
- 知足常樂Lv 75 年前
四個情況，因此是 4 × 3! = 24。