Why does tennis score 15, 30, and 40? Tennis is a different scoring system on the court. Like the clock face of the tennis score, with a quarter move of the minute hand to indicate a score of 15, 30, and 45, when the hand moves to 60 the is over. But the score stays within 60 ticks on the clock face but 45 changes to 40.
https://pressurelesstennisball.com/what-is-the-term-when-a-tennis-game-is-tied-at-40-40