Find How Many Read None and Magazine C Only
Question:
In a survey of 100 persons it was found that 28 read magazine A, 30 read magazine B, 42 read magazine C, 8 read magazines A and B, 10 read magazines A and C, 5 read magazines B and C and 3 read all the three magazines. Find:
(i) How many read none of three magazines?
(ii) How many read magazine C only?
Solution
\[ n(A\cup B\cup C) \] \[ =28+30+42-8-10-5+3 \] \[ =80 \](i)
\[ \text{None}=100-80 \] \[ =20 \](ii)
\[ \text{C only}=42-10-5+3 \] \[ =30 \]Hence,
\[ \boxed{\text{None}=20} \] \[ \boxed{\text{C only}=30} \]