Lab Partners

Let's use a constructive approach to solving this problem, by looking at the problem from Linda's point of view. We can ask ourselves,"What's the probability that she will be matched with her friends Martin and Nancy?" $2$ of the other $14$ students are randomly chosen to be paired with her. There are $\binom {14}{2}=91$ ways that this can be done, and only 1 of those ways pairs Martin and Nancy with her. Therefore, the probability is $\boxed{\frac{1}{91}}$ .