1. The problem states that in a survey of 100 people, 60 liked coffee, 40 liked tea, and 20 liked both coffee and tea. 2. We need to find how many people liked only coffee. 3. Use the formula for the number of people who liked only coffee: $$\text{Only Coffee} = \text{Coffee} - \text{Both}$$ 4. Substitute the values: $$\text{Only Coffee} = 60 - 20$$ 5. Calculate the result: $$\text{Only Coffee} = 40$$ 6. Therefore, 40 people liked only coffee.