Three segments are given on the number line:
B = [0; 70],
C = [30; 60] and
D = [20; 90]. Specify
the smallest possible length of such a segment
A for which the logical expression
\((((x \in B) \rightarrow (x \in C)) \wedge (x \in D) ) \rightarrow (x \in A)\)
true (i.e. takes the value 1) for any value of the variable
x.