Dice sums with 6 dice

71 Views Asked by At

If we throw 8 dice and take the sum of the highest 4 outcomes, What is the probability that the sum equals to 24? I think in order to get sum 24, at least there are 4 times 6s among 8 dices. But how can i get the equation for this problem?

1

There are 1 best solutions below

0
On

This solution does not require any knowledge of probability distributions. However I would suggest looking into it as it makes the problem much easier.

You need at least 4 sixes. Let's find the probability of obtaining exactly 4 sixes and you can do the rest. How many ways can you get exactly 4 sixes out of 8 dice? $8\choose 4$. What is the probability associated with each of these events? $(\frac 16)^4×(\frac56)^{8-4}$. Thus the probability of getting exactly 4 sixes is $8\choose 4$$(\frac16)^4(\frac56)^4$.

Find the probabilities of obtaining exactly 5,6,7,8 sixes in a similar fashion. Add them up. It should give you the answer.