A die is rolled and two events A and B are defined as follows.
A: An odd number turns up
B: A prime Number turns up
Find the value of 36 P(A ∪ B).
we will use the result P(A ∪ B) = P(A) + P(B) − P(A ∩ B) to find the answer in the first method.
P(A) = P(an odd number) = 36 = 12
similarly,P(B) = P({ 2,3,5 })=12
P(A intersection B) =P({ 3,5 })
=26
=13
⇒ P(A ∪ B) = 12 + 12 − 13
=1 − 13
=23
In the second method,we will find the set A ∪ B and find P(A ∪ B)
A ∪ B ={ numbers which are prime or odd }
={ 1,2,3,5, }
⇒ P(A ∪ B) =P({ 1,2,3,5, })
= 46
=23
⇒ Answer =36 × 23
=24