Spot the false claim in each trio

Exercise and reference answers

Questions

1. False statement

   The event A but not B is the union of A and B'.

   Statements

   1. The event A or B is the union of A and B.
   2. The event A and B is the intersection of A and B.
   3. The event A but not B is the union of A and B'.

2. False statement

   P(not A) equals 1 + P(A).

   Statements

   1. P(not A) equals 1 + P(A).
   2. Not A holds every outcome of S that is missing from A.
   3. A and not A are mutually exclusive and exhaustive.

3. False statement

   P(A or B) equals P(A) + P(B) for every pair of events.

   Statements

   1. P(A or B) equals P(A) + P(B) - P(A and B) for any two events.
   2. P(A or B) equals P(A) + P(B) for every pair of events.
   3. When A and B are mutually exclusive, P(A and B) is 0.

Instructions

Three claims appear each round. Tap the single one that is false.

Explanation