Set and Venn-diagram
Set is the collection of well defined object.
Q) Among 210
students, 85 passed in English, 125 passed in Nepali, and 25 failed in both
subjects. Find the number of students who passed in both subjects and
illustrate the result in a venn-diagram.
Soln:
Here,
n(U) = 210
n(E) = 85
n(N) = 125
n(EUN)' =
25
n(EnN) = ?
Now
n(U) = n(E) + n(N) – n(EnN) + n(EUN)'
210 = 85 + 125 –n(EnN) + 25
210 = 210 – n(EnN) + 25
210 = 235 – n(EnN)
n(EnN) = 235 – 210
n(EnN) = 25
Therefore, 25 students passed in both subjects.
