Prep T2 PS Q66

[gan4sula]

66. 7431-!-item-!-187;#058&005458
From a group of 21 astronauts that includes 12 people with previous experience in space flight, a 3-person crew is to be selected so that exactly 1 person in the crew has previous experience in space flight. How many different crews of this type are possible?

(A) 432
(B) 594
(C) 864
(D) 1,330
(E) 7,980

請問有人可以列式嗎
謝

[hey]

(12!/1!11!)*(9!/2!7!)=432

[gan4sula]

(12!/1!11!)*(9!/2!7!)=432

感謝hey 大
聯cr也熱心回覆

原來是只要一組人, 我以為他說21人要分7組一組3人1個有經驗, 這樣共有幾總組合

哈我常看不懂題目