Question

a pattern of letter arrangements begins with the 3 steps below,
A
ABA
ABCBA

what are the next 3 steps, how many letters are in the 3 above and how many letters are in the 10th step?

Answer 1

next 3 steps:

ABCDCBA
ABCDEDCBA
ABCDEFEDCBA

Patern: add 2 letters

1. 1
2. 3
3. 5
4. 7
5. 9
6. 11
7. 13
8. 15
9. 17
10. 19

The 10th step has 19 letters