Answer:
16666.25
Explanation:
For rounded values, the minimum value they could have been rounded from is the given value less half its least-significant digit.
That means the minimums are ...
a: 340 ⇒ 340 -5 = 335
b: 49.8 ⇒ 49.8 -0.05 = 49.75
Then the minimum product would be ...
(335) × (49.75) = 16666.25