50 people were asked if they like tea, coffee and hot chocolate.
Every person liked at least one of the drinks.
17 of the people like all three drinks.
31 of the people like hot chocolate
34 of the people like tea.
21 of the people like tea and coffee.
7 of the people like tea and hot chocolate but not coffee
2 of the people like coffee and hot chocolate but not tea
Two of the 50 people are chosen at random.
Work out the probability that they both like coffee