Question 13
To keep Bonnie from understanding Bean and Tom's conversation, they encode messages using 12 digits, each 0 or 1. Decoding has two steps:
- Step 1: Replace adjacent pairs of digits with A, B, C or D according to this table.
| Pair | 00 | 01 | 10 | 11 |
|---|---|---|---|---|
| Letter | A | B | C | D |
- Step 2: In the resulting letter sequence, replace consecutive pairs of letters according to this table.
| Pair | AA | AB | AC | AD | BA | BB | BC | BD | CA | CB | CC | CD | DA | DB | DC | DD |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Output | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F |
After receiving an encoded message, Bean decodes it as C13.
Which code did Bean receive?
- Step 1: Replace adjacent pairs of digits with A, B, C or D according to this table.
| Pair | 00 | 01 | 10 | 11 |
|---|---|---|---|---|
| Letter | A | B | C | D |
- Step 2: In the resulting letter sequence, replace consecutive pairs of letters according to this table.
| Pair | AA | AB | AC | AD | BA | BB | BC | BD | CA | CB | CC | CD | DA | DB | DC | DD |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Output | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F |
After receiving an encoded message, Bean decodes it as C13.
Which code did Bean receive?