How are we supposed to know if we’re right, if you don’t post answers? My guesses:
#1: Either: fold one of the ropes to be 3/4 of it’s original size, burn the other down to that length, then burn again to give 45 minutes; or just start burning one rope at 3/4, one side will burn for 15 mins, the other for 45. #2: Putacork that is too small in, and it will just fall into the bottle. Turn it over to get the coin out. #3: Look inside the bags. Christ. #4: Makeamental note where the water-line is. Put your hand tightly on top of the glass and turn it over. If the water is at the same spot, it was half full. #5: Seen this one so many times before.