There are three segments on the number line:
B = [25; 80],
C = [60; 75] and
D = [70; 90]. Specify
the smallest possible length of such a segment
A for which the logical expression
\(((x \in C) \neq (x \in B)) \rightarrow (x \in D) \ vee (x \in A)\)
true (i.e. takes the value 1) for any value of the variable
x.