The sequence is 11n+1 as the difference between each number is 11 and if you substitute 1 for n, you must add 1 to 11 to make 12. This sequence works for the other numbers as well. To find out the height of the plant on the 15th day, just substitute 15 for n: (11 x 15)+1=166mm is the height of the plant in 15 days.
