# integers

• Feb 2nd 2010, 02:07 AM
sri340
integers
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?
• Feb 2nd 2010, 02:53 AM
arze
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.
• Feb 7th 2010, 12:29 PM
Morlaf
i make 4/5.
if you need me to elaborate (or if you disagree) please let me know.....

thanks,
Morlaf
• Feb 7th 2010, 01:09 PM
Plato
Quote:

Originally Posted by arze
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\$.
• Feb 7th 2010, 03:48 PM
arze
Quote:

Originally Posted by Plato
The mean of \$\displaystyle \{3,5,6\}\$ is less than five, but \$\displaystyle 3+5+6=14\$.

oops! my bad thanks for pointing out!