Set A: {1, 3, 4, 6, 9, 12, 15}
If three numbers are randomly selected from set A without replacement, what is the probability that the sum of the three numbers is divisible by 3?  Choose the correct choice from the following answers:
A) 3/14 B) 2/7 C) 9/14 D) 5/7 E) 11/14
Probability of an event = (# of favorable outcomes) / (total # of outcomes).   There are 5 numbers you can choose from (3, 6, 9, 12, 15) so that the sum to be divisible by 3 and there are total of 7 numbers so P=C35C37=27P=C53C73=27.   Answer: 2/7.
<result>B</result>
Set A: {1, 3, 4, 6, 9, 12, 15}
If three numbers are randomly selected from set A without replacement, what is the probability that the sum of the three numbers is divisible by 3?