Does hero Gandalf's card text apply to the riddles in that quest?

You announce before you shuffle and discard, but you could know if paying a ressource help you with the riddle.

But you could not discard the number of cards noted on the encounter card and then see the top card and know if that card would be worth one resource from Bilbo for an automatic success if it is a correct card?

You could, that what I was saying. Once you fail the riddle, you still can decide to pay an additionnal resource and Gandalf will then passively show you your next cards, so you could know if it is a success.

Thanks, sorry if I didn't get exactly what you wrote.