Concept:
Conditional probability = Favorable Total (given condition)
Step 1: Condition: sum of digits = 8.
Possible pairs (tens, units):
\[
(0,8),(1,7),(2,6),(3,5),(4,4)
\]
Step 2: Total outcomes = 5.
Step 3: Product = 7 only for:
\[
(1,7)
\]
Step 4: Favorable outcomes = 1.
Step 5: Probability:
\[
P = \frac{1}{5}
\]
Conclusion:
Answer = $\frac{1}{5}$