Question

Help me please show your solution ​

Answer 1

Rule: Multiply ×3 in turn

First term is 5

Explanation:

5,15,45,135,405,1215

Multiply ×3 to find after series

and ÷3 to find before series

Example

45 ÷ 3 = 15{second term}

15 ÷ 3 = 5 {first term}