James and Jonathan are liars, who lie on specific days.
James lies on Fridays, Saturdays and Sundays, but he is honest on all other days.
Jonathan lies on Tuesdays, Wednesdays and Thursdays, but he tells the truth on all other days.
On what day of the week would they both say “Tomorrow, I will lie.”?
When they both say "Tomorrow, I will lie."
James is telling the truth and Jonathan is Lying as it is Thursday.