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📐 Mathematics  ·  Relations and Functions  ·  JEE

In a survey of 100 people, 60 read newspaper A, 40 read B, 20 read both. How many read neither?

Answer: 20.

  • A 10
  • B 20
  • C 30
  • D 40

Correct answer: B. 20

Explanation: Inclusion-exclusion principle: |A∪B| = |A|+|B|-|A∩B| = 60+40-20 = 80. Total surveyed = 100. Neither = 100-|A∪B| = 100-80 = 20. Answer: 20 people read neither

Concept context

Ordered pairs, Cartesian products, types of relations and functions, domain and range. Foundation for calculus and Class 12 algebra.

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