Three integers are randomly selected without replacement from the set { 1,2,3,5,6,7}. What is the probability that the mean of the values chosen is less than, but not equal to, 5?
since the mean is less than 5, the sum of the 3 numbers will be less than or equal to 12. so find the sums of three of the numbers in the set that are less or equal to twelve.
since the mean is less than 5, the sum of the 3 numbers will be less than or equal to 12. so find the sums of three of the numbers in the set that are less or equal to twelve.
The mean of $\displaystyle \{3,5,6\}$ is less than five, but $\displaystyle 3+5+6=14$.