两个数学都很简单, 分别提前20和15分钟做完。
有道提需要提醒下: Given total number of students as 125 (注意,不是120!!!!!)
Number of students learning Spanish = 40
Number of students learning French = 60
Number of students learning Russian = 80
Number of students learning 2 languages = 50
Number of students learning all 3 languages = 10
Find number of students learning none of these languages?
答案: 125-(40+60+80-50-10*2)=15