Julie thought that her watch was 5 minutes fast, so she thought that it was currently 8:05 pm. In actual fact, her watch was 5 minutes slow, so it was really 7:55 pm. Julie deliberately turned up 10 minutes late, so she arrived at the cinema at 8:05 pm.

John thought that his watch was 5 minutes slow, so he thought that it was currently 7:55 pm. In actual fact, his watch was 5 minutes fast, so it was really 8:05 pm. John decided to turn up 10 minutes early, so he arrived at the cinema at 7:55 pm.

Since John arrived at the cinema first, he had to wait for 10 minutes for Julie to arrive. Therefore, John turned up first and had to wait for 10 minutes for Julie to arrive.