math
posted by bill on .
1. In a survey of a TriDelta chapter with 46 members, 13 were taking mathematics, 33 were taking English, and 6 were taking both. How many were not taking either of these subjects?

No One was Not taking any of these,Because 33+13=46

N(Math OR English) = N(Math) + N(English)  n(Math AND English)
= 13 + 33  6
= 40
So 40 took either Math or English, then
6 took neither of these subjects
You can also do this with Venn diagrams 
Subtract 6 from 13 and from 33.
Then add 6 back just once.
7 + 27 + 6 = 40 students are taking either one or both of the subjects.
So 46  40 = 6 students are taking neither of the subjects.