Ted [T and T = T] or [F and T = F] or [T and F = F] or [F and F = F] Ned unknown Fred All 3 sentences must be True or all 3 must be False because they are separate sentences, unlike Ted's sentence.If Fred is Blue, then Ned is Blue and Ted is Red. If Fred is red, then Ned is red and Ted is blue. For Ted the combination of F [I'm Blue] and T [They're both red] is not a possibility. Likewise for the T and F combination. You are left with:
Ted [T and T = T] or [F and F = F] Ned unknown Fred [T and T and T] or [F and F and F] -- same as beforeThe given is there is at least 1 Red and 1 Blue man. If you assume that Fred could not have heard Ned as well, then you pick up Ted. Otherwise, you would pick up both Ned and Fred.