阿摩線上測驗
11. At a gathering of 20 people, there are 15 people who all know each other and 5 people who know
no one. People who know each other hug, and people who do not know each other shake hands.
How many handshakes will occur?
(A) 75
(B) 85
(C) 90
(D) 100
答案：登入後查看
統計： A(12), B(13), C(5), D(7), E(0) #3125589
統計： A(12), B(13), C(5), D(7), E(0) #3125589
