Premise:
"but who knows"
Hypothesis: Your guess is as good as any.

yes

Premise:
"I dare say he's dashed off there now, thought Tuppence."
Hypothesis: Tuppence believes he made a quick run to the place at that moment.

yes

Premise:
"Postal Service and all other national posts is that they provide service to every address in the countries they serve."
Hypothesis: Not every national post service provides service to every possible address.
it is not possible to tell