Rustlers' Rhapsody/Fridge

When Rex and Peter find themselves in "the big shootout", stuck in a canyon below 20 ornery gunmen, Rex announces "I made a mistake. We can't beat this many men. Usually about 40% chicken out." If 40% of the 20 gunmen had chickened out, that would leave 12 of them -- and Rex had two revolvers containing 6 bullets each.