Given three distinct digits a, b and c, it is possible, by choosing two digits at a time, to form six two-digit numbers. Determine all possible sets {a, b, c} for which the sum of the six two-digits numbers is 484.

To determine all possible sets \(\{a, b, c\}\) for which the sum of the six two-digit numbers is 484, we start by expressing the sum of these numbers in terms of \(a\), \(b\), and \(c\).

1. **Form the six two-digit numbers:**
   The six two-digit numbers formed by choosing two digits at a time from \(\{a, b, c\}\) are:
   \[
   10a + b, \quad 10a + c, \quad 10b + a, \quad 10b + c, \quad 10c + a, \quad 10c + b
   \]

2. **Sum the six two-digit numbers:**
   \[
   (10a + b) + (10a + c) + (10b + a) + (10b + c) + (10c + a) + (10c + b)
   \]

3. **Combine like terms:**
   \[
   = 10a + b + 10a + c + 10b + a + 10b + c + 10c + a + 10c + b
   \]
   \[
   = (10a + 10a + a + a) + (10b + 10b + b + b) + (10c + 10c + c + c)
   \]
   \[
   = 22a + 22b + 22c
   \]

4. **Set the sum equal to 484:**
   \[
   22a + 22b + 22c = 484
   \]

5. **Simplify the equation:**
   \[
   22(a + b + c) = 484
   \]
   \[
   a + b + c = \frac{484}{22}
   \]
   \[
   a + b + c = 22
   \]

6. **Determine possible sets \(\{a, b, c\}\):**
   Since \(a\), \(b\), and \(c\) are distinct digits (0-9), we need to find all sets of three distinct digits that sum to 22.

   - **Case 1: The largest digit is 9.**
     \[
     a + b + c = 22 \implies 9 + b + c = 22 \implies b + c = 13
     \]
     Possible pairs \((b, c)\) are:
     \[
     (4, 9), (5, 8), (6, 7)
     \]
     Thus, the sets are:
     \[
     \{9, 4, 9\}, \{9, 5, 8\}, \{9, 6, 7\}
     \]

   - **Case 2: The largest digit is 8.**
     \[
     a + b + c = 22 \implies 8 + b + c = 22 \implies b + c = 14
     \]
     Possible pairs \((b, c)\) are:
     \[
     (6, 8), (7, 7)
     \]
     Thus, the sets are:
     \[
     \{8, 6, 8\}, \{8, 7, 7\}
     \]

   - **Case 3: The largest digit is 7 or less.**
     The largest possible sum here is:
     \[
     7 + 7 + 7 = 21
     \]
     which is less than 22, so there are no valid sets in this case.

7. **Conclusion:**
   The valid sets of digits \(\{a, b, c\}\) are:
   \[
   \{9, 4, 9\}, \{9, 5, 8\}, \{9, 6, 7\}, \{8, 6, 8\}, \{8, 7, 7\}
   \]

The final answer is \( \boxed{ \{9, 4, 9\}, \{9, 5, 8\}, \{9, 6, 7\}, \{8, 6, 8\}, \{8, 7, 7\} } \)