Three segments are given on the number line:
B = [10; 40],
C = [20; 85] and
D = [70; 90]. Specify
the largest possible length of such segment
A for which the logical expression
\((x \in A) \rightarrow ((x \notin B) \rightarrow ((x \in C) \ wedge (x \in D)))\)
true (i.e. takes the value 1) for any value of the variable
x.