A bag contains 5 red smileys, 6 yellow smileys and 3 green smileys. If two smileys are picked at random, what is the probability that both are red or both are green in colour?

Given total number of smileys = 5 + 6 + 3 = 14

Now, required probability = 

$\frac{5C2}{14C2} + \frac{3C2}{14C2} = \frac{10}{91} + \frac{3}{91} = \frac{13}{91} = \frac{1}{7}$