so from 4.00-4.10 10minutes has passed and thelma would have travelled 10/60×54 = 9 miles. In 1 hour , georgia would have travelled 10 miles more than thelma, hence in 9/10 hours she would catch up with thelma.
9/10 × 60 = 54 minutes . hence the ans is 54 minutes or 9/10 hours