Problem 3. In the school, there are 50 teachers, of whom 29 drink coffee, 28 drink tea, and 16 do not drink either coffee or tea. How many teachers drink only coffee, and how many drink only tea?
Solution. Since 16 teachers do not drink either coffee or tea, we get that $50-16=34$ teachers drink either coffee or tea. However, 28 teachers drink tea, and 29 drink coffee, so $(28+29)-34=57-34=23$ teachers drink

![](https://cdn.mathpix.com/cropped/2024_06_05_0c08f972e294b2535969g-05.jpg?height=264&width=397&top_left_y=827&top_left_x=1056)
both coffee and tea. Only coffee is drunk by $29-23=6$ teachers, and only tea is drunk by $28-23=5$ teachers.