Marty and Jill want to copy three 60 minute tapes. They have two tape recorders that will dub the tapes for them, so they can do two at a time. It takes 30 minutes for each side to complete; therefore in one hour two tapes will be done, and in another hour the third will be done. Jill says all three tapes can be made in 90 minutes. How?
Jill will rotate the three tapes. Let's call them tapes 1,2, and 3 with sides A and B. In the first 30 minutes they will tape 1A and 2A, in the second 3 minutes they will tape 1B and 3A (Tape 1 is now done). Finally, in the last 30 minutes, they will tape 2B and 3B.
A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?
Two soldiers, William and Ethan, are assigned to guard a bridge, which connects the West and East sides of the Great Kingdom. Each soldier is ordered to stand at an end of the bridge to make sure no criminals cross.
On one side of the bridge stands William, watching over the West side of the kingdom, and making sure no shady characters try to cross the bridge.
Ethan stands on the other side of the bridge, facing the East side of the kingdom with his rifle at the ready in case any criminals try to pass across.
"Any criminals today?" William asks.
Ethan rolls his eyes. "What do you think?" he asks.
"You roll your eyes too much," William says.
How could William tell that Ethan was rolling his eyes?
William is on the east side of the bridge, facing the West side of the kingdom, while Ethan is on the west side of the bridge, facing the East side of the kingdom. So William and Ethan are facing each other, and can see each other's faces.
