Riddles and Puzzles

Riddles and Puzzles # 156

Two students learning the English language were studying for their next test, and the major topic was about time. On their way to school they were practicing.

"When the day after tomorrow is yesterday," said Priscilla, "then 'today' will be as far from Sunday as that day was which was 'today' when the day before yesterday was tomorrow!"

On which day of the week did they have this conversation?