Question

Which of the following is a correct representation of inclusion exclusion principle (|A,B| represents intersection of sets A,B)?

(a) |A U B|=|A|+|B|-|A,B|

(b) |A,B|=|A|+|B|-|A U B|

(c) |A U B|=|A|+|B|+|A,B|

(d) |A,B|=|A|+|B|+|A U B|

The question was asked in final exam.

Enquiry is from Number Theory topic in portion Number Theory of Data Structures & Algorithms II

Answer 1

The correct option is (a) |A U B|=|A|+|B|-|A,B|

Explanation: The formula for computing the union of two sets according to inclusion-exclusion principle is |A U B|=|A|+|B|-|A,B| where |A,B| represents the intersection of the sets A and B.