Step 1: Understanding the Concept:
Identify the relationship between the numbers by looking for repeating constants and arithmetic operations. Step 2: Identifying the Vector of Change:
The pattern consists of a repeating group of three:
1. The first number decreases by 3 to get the second ($28 - 3 = 25$).
2. The third number is a constant '5' used as a separator.
3. The next group begins by subtracting 4 from the previous significant number ($25 - 4 = 21$).
4. Then subtract 3 ($21 - 3 = 18$), followed by the constant '5'. Step 3: Calculation:
Following the sequence, after the constant '5', we subtract 4 from 18 to get 14. To find the next pair:
- Subtract 3 from 14: $14 - 3 = 11$.
- Insert the constant: 5. Step 4: Final Answer:
The next pair of numbers is 11 and 5. Thus, the correct option is (a).