Answer:
The value of b is, 8
Step-by-step explanation:
Determine the value of b;
Given:
....[1]
Since, 0x6A represents the hexadecimal form.
First convert this hexadecimal form into decimal form:

⇒
(decimal form)
Now we have to convert this decimal form into octal
8 | 106
8 | 13 | 2
| 1 | 5
1
Then, the octal form we get, 
Substitute these in [1] we have;
On comparing both sides we get;
b = 8
Therefore, the value of b is, 8