Official solution
C \[ \to \] person like coffee
T \[ \to \] person like Tea
n(C) = 73
n(T) = 65
n(C \[ \cup \] T) \[ \le \] 100
n(C) + n(T) -- n (C \[ \cap \] T) \[ \le \] 100
73 + 65 -- x \[ \le \] 100
x \[ \ge \] 38
73 -- x \[ \ge \] 0 \[ \Rightarrow \] x \[ \le \] 73
65 -- x \[ \ge \] 0 \[ \Rightarrow \] x \[ \le \] 65
\[ \therefore \] 38 \[ \le \] x \[ \le \] 65