Q: In a nation wide poll, N people were interviewed on 2 questions. If 1/4 of them answered "Yes" to Question 1 and of those, 1/3 answered "Yes" to question 2, which of the following expressions represents the number of people who did not answer "Yes" to both questions

n/7

6n/7

5n/12

7n/12

11n/12

My approach

People who answered Q1 = n/4
People who answered Q2 = n/12
Total number of people who answered Yes = 1/4 + 1/12 = 1/3
People who did not answer yes to both the question = 1 -1/3 = 2n/3 .

Approach 2: I tried to solve it by double set amtrix as well, but that consused me more as I found that information was missing, because I did not knew how many people answered both the questions YES, How many people naswer Yes to 1 and No to 2 and how many answered Yes to 2 and no to 1.

Can Some one please explain.

The OA is E - 11N/12