Alice travelled from Town X to Town Y, and then to Town Z. The total time she took to travel from Town X to Town Z, when rounded to the nearest 10 minutes, was 3 h 20 min. The time she took to travel from Town X to Town Y, when rounded to the nearest 10 minutes, was 2 h 10 min. Determine the upper and lower bounds of the time Alice took to travel from Town Y to Town Z. Give your answers in minutes.