Question 1086705: Two dice are rolled together. What is the probability that:
a)The first die shows 1 or the second die shows 4?
B)The first die shows odd number and the second die shows prime number?
c)The first die shows odd number or the second die shows prime number?
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! There are 6 * 6 = 36 possible outcomes
:
a) Probability(P) of 1st die is a 1 is 6/36 and P of 2nd die is a 4 is 6/36
P(rolling a 1 or a 4)) = (6/36) + (6/36) = (1/6) + (1/6) = 2/6 = 1/3
:
b) P(1st die is odd number) = 18/36 = 1/2, P(2nd die is a prime numbers) = 24/36 = 2/3
---Note prime numbers are 2, 3, 5
P(rolling odd number and a prime number) = (1/2) * (2/3) = 2/6 = 1/3
:
c) P(rolling odd number or a prime number) = (18/36) + (18/36) - (9/36) = 3/4
:
---Note we have to subtract the 9 events where the first die is a 1, 3 or 5 and second die is 2, 3, 5 since we already counted them
:
|
|
|
