35. It is said that when asked how many students he had, the ancient Greek mathematician Pythagoras answered: “Half of my students study mathematics, a quarter study nature, a seventh part spends time in silent contemplation, and the remaining part consists of 3 maidens.” How many students did Pythagoras have?
35. 36) $\frac{1}{2}+\frac{1}{4}+\frac{1}{7}=\frac{25}{28}$; 2) $1-\frac{25}{28}=\frac{3}{28}$; 3) $3: \frac{3}{28}=28$.