Question

I roll a six-sided die 4 times. Find chances for each of the following events: a) the first die roll is bigger than the second or the first roll is a

Answer 1

=0.5278

Explanation:

a) The first die roll is bigger than the second or the first roll is a 3

Cases for 2 rolls are (1,1)(1,2)(1,3)....(1,6),(2,1)(2,2)..... (total 36)

We will get 6 cases when they are equal and 15 when 1st is bigger and 15 when 1st is smaller

So Let A is the event when first roll bigger

B is the event when First roll=3

So

P(A)=15/36

P(B) =1/6

P(A and B)=2/36

So

P(A or B)=P(A)+P(B)-P(A and B)

=15/36+1/6-2/36

=19/36

=0.5278