A group of people went to a coffee shop. Each person chose a drink and a treat. Drink Coffee Treat Muffin Tea Tart number of people who chose coffee: number of people who chose tea = 1:4 Of those who chose coffee, number of people who chose a muffin: number of people who chose a tart = 2:7 Of those who chose tea, number of people who chose a muffin: number of people who chose a tart = 5:1 What fraction of the people chose a tart? You must show how you get your answer.