Question 693:

Asked on April 21, 2009

Tags: Probability , Union , Joint Probability

1

Answer:

No answer provided yet.This question involves understanding that a king can also be a diamond, so we need to the non-overlapping joint probabilities of these events. These two events are not independent since as stated, we can have a king and diamond, so we cannot multiply their probabilities together.

We need to add together the probabilities to get the Union of the events. However, when adding together the probabilities we'll be double counting the instance of the king of diamonds, so we need to subtract that out. 

The formula for (A U B) =P(A) + P(B) - P(A n B) where P(A n B) is the intersection or 1/52, since there is only 1 king of diamonds.  Filling in the values we get: 4/52 + 13/52 - 1/52 and expressed as percentages : .076923 + .25 - .019231 = .307692.

So the probability of drawing either a king or diamond is .307692.