three teachers are to be randomly selected from fourteen teachers. Of the fourteen teachers, 3 are from school A, seven are from school B, and four are from school C. What is the probability that the three selected will not include any of the teachers from school A?

Question

three teachers are to be randomly selected from fourteen teachers. Of the fourteen teachers, 3 are from school A, seven are from school B, and  four are from school C. What is the probability that the three selected will not include any of the teachers from school A?

dumbcow · Answer

take away the three from school A, and you are left with 11 teachers of which to choose 3

using combinations:
$$\rightarrow P = \frac{11C3}{14C3}$$

anonymous · Answer

wow that is so much simpler than how i did it, i worked out all the ways in which teachers from A could be part of the 14 and then took that away from the total (14C3), woww