Without prophecy, how could they possibly know what happened, and answer the riddle?
Malbim (12): Shimshon said (verse 12) "u'Metzasem", to hint that if they search, they will find [the answer]. And other matters were in their favor. There were 30 of them, and they had 14 days to answer, and each was in danger of losing only one outfit, and Shimshon could lose 30. 1
How is this is in their favor? If they win, each man gets one outfit, the amount that he could have lost. Also Shimshon, if he wins, gets the amount that he could have lost! (PF)
Why does it say that they could not answer for three days?
Malbim: For three days they investigated. After this they decided that it is a hidden matter, and despaired of investigating. However, they could not ask his wife to entice him until after the Nisu'in.
