The lengths of time in minutes to swim a certain distance by the members of a class of twelve 9-year-olds and by the members of a class of eight 16-year-olds are shown below.

9-year-olds: 13.0, 16.1, 16.0, 14.4, 15.9, 15.1, 14.2, 13.7, 16.7, 16.4, 15.0, 13.2

16-year-olds: 14.8, 13.0, 11.4, 11.7, 16.5, 13.7, 12.8, 12.9

(i) Draw a back-to-back stem-and-leaf diagram to represent the information above.

(ii) A new pupil joined the 16-year-old class and swam the distance. The mean time for the class of nine pupils was now 13.6 minutes. Find the new pupil’s time to swim the distance.