180. In a nationalwide poll, N people were interviewed. If 4/4 of thm answered "yes" to question 1, and of those, 1/3 answered 'yes" to question 2. which of the following expressions represents the numver of people interviewed who did not answer "yes" to both questions? a. n/7 b. 6n/7 c. 5n/12 d. 7n/12 e. 11n/12 答案：e 想不通。莫非是问没有同时回答yes的人是多少？ | 
