Question:
In a town of 840 persons, 450 persons read Hindi, 300 read English and 200 both. Then the number of persons who read neither is
(a) 210
(b) 290
(c) 180
(d) 260
Solution:
Total persons in a town is 840
Let H denote set of persons who read Hindi
Let E denote set of persons who read English
Then n(⋃) = 840, n(H) = 450, n(E) = 300
Then n(H⋃E)' = n(⋃) – n(H⋃E)
= n(⋃) – [n(H) + n(E) – n(H⋂E)]
= 840 – [450 + 300 – 200]
= 840 – 550
n(H⋃E)' = 290
Therefore, the number of persons who read neither is 290.
Hence, the correct answer is option B.