67.2k views
4 votes
Sandra wrote the sequence shown 3 6 11 18 and 27 I need to find the 12th term in the sequence

User Hives
by
3.3k points

1 Answer

5 votes

Given sequence is 3, 6, 11, 18, 27

The given sequence is not arithmetic or geometric as it does not have a common difference or ratio. Therefore, we have to evaluate it using a different way.

Let's say

6 - 3 = 3

11 - 6 = 5

18 - 11 = 7

27 - 18 = 9

That means we are adding odd terms to the last digit to get the next one. For example, we added 9 to 18 to get the fifth term. Next time, the odd number will be increased and added to 27 to get the 6th term. For example,

6th term = 27 + 11 = 38

The general formula would be

Nth term = (N-1)th term + (2n - 1)

Similalrly,

7th term = 6th term + (2(7) - 1)

7th term = 38 + 13

7th term = 51

Using the above formula, we can calculate the other terms

8th term = 51 + 15 = 66

9th term = 66 + 17 = 83

10th term = 83 + 19 = 102

11th term = 102 + 21 = 123

and

12th term = 123 + 23 = 146

Therefore, the 12th term in this sequence would be 146.

User Avindu Hewa
by
3.8k points