Question

You roll a 6-sided die.
What is P(greater than 4 or factor of 5)?

Answer 1

P(greater than 4 or factor of 5) = 1/3

Explanation:

→ let A be the set {the numbers greater than 4}

then A : {5 , 6}

p(A) = 2/6

→ let B be the set {the factors of 5}

then B : {1 , 5}

p(B) = 2/6

P(greater than 4 or factor of 5) = p(A∪B)

Formula =================

p(A∪B) = p(A) + p(B) - p(A∩B)

………………………………………………

A∩B : {5}

then

cardA∩B = 1

Then

p(A∩B) = 1/6

Finally :

p(A∪B) = p(A) + p(B) - p(A∩B)

= 2/6 + 2/6 - 1/6

= 3/6

= 1/3