Two dice of different colors are thrown simultaneously. The probability that the sum of the faces appeared is either $7$ or $11$ is
- $\dfrac7{36}$
- $\dfrac49$
- $\dfrac23$
- $\dfrac59$
The answer is $\dfrac49$ but why?
What I did was:
Total Outcomes = $36$
Sum is $7 = (1,6), (6,1), (2,5), (5,2), (3,4), (4,3)$
Sum is $11 = (5,6), (6,5)$
Probability $= \dfrac8{36} = \dfrac29$
Where am I wrong?
Best Answer
You are very much correct, also, 4/9 is not even an answer in the choices given.
Probability of the sum being 7 = 6/36 = 1/6 = 3/18 Probability of the sum being 11 = 2/36 = 1/18 Probability of the sum being 7 or 11 = 1/18 + 3/18 = 4/18 = 2/9