Question

You roll a six-sided die.

Event A: Roll an odd number.
Event B: Roll a number less than 5.
Find P(A or B). Express you answer as a fraction in simplest form.

Answer 1

P(A or B) =

Formula: P(AUB)=P(A)+P(B)-P(A n B)

We roll six-sided die.

Then sample space ={1,2,3,4,5,6}

And

Event A: Roll an odd number.

Odd numbers are {1,3,5}

Event B: Roll a number less than 5

Number less than 5 are {1,2,3,4}

So, Probability P(A)=

Probability P(B)=

Now, the odd number which is less than 5 are {1,3}

So, P(A n B)=

Since P(AUB)=P(A)+P(B)-P(A n B)

Therefore, P(A or B) = 1/6