In a nationwide poll, P people were asked 2 questions. In 2/5 answered “yes” to question 1, and of those 1/3 also answered yes to question 2, which of the following represents the number of people polled who did not answer “yes” to both questions ?
e) None of these
If you are not comfortable with algebra, you can substitute suitable values in place of variables.
Let's say p = 30 (i.e. only 30 people were surveyed)
Out of these 30, 2/5 said 'yes' to Q1. This implies 2/5*30 = 12 said 'Yes' and thus 18 said 'No'
Out of these 12, 1/3 said 'yes' to Q2 as well. This implies 1/3*12 = 4 said 'yes' to both Q1 and Q2.
Thus the remaining 26 people would not have said "yes" to both questions and our ratio is 26/30 = 13/15