Use rules of inference to show that "If 'Zoom' does not interfere or if 'Lex' does not interfere, then 'the Superman' and 'the Flash' will race and 'the Batman' will watch.", "If 'the Superman' and 'the Flash' did race, then there was a winner" and "There was not a winner" imply the conclusion that "'Lex' interfered".

Let Z: Zoom interfered;

L: Lex interfered;

R: The Superman races the Flash;

W: There is a winner;

B: Batman watches