Toasting Bread

Your toaster is broken, so you decide to toast your bread in a pan. The pan can hold three slices of bread at a time and takes 1 minute to toast one of their sides. How much time would it take you to toast four slices of bread on both sides using the pan?

It would take you 2 minutes and 40 seconds. Label the slices with A, B, C, D, their top sides A1, B1, C1, D1, and their bottom sides A2, B2, C2, D2.

  1. Toast A1, B1, C1 for 40 seconds.
  2. Toast A2, B2, D1 for 40 seconds.
  3. Toast A1, C2, D2 for 20 seconds.
  4. Toast A2, C2, D2 for 20 seconds.
  5. Toast B1, C1, D1 for 20 seconds.
  6. Toast B2, C2, D2 for 20 seconds.

100 Guests in 99 Rooms

One hundred people entered a hotel that had 99 rooms, and each of them asked for their own room. In order to solve the problem, the bellboy did the following:

He asked the 100th guest to wait for a while with the 1st guest in room number 1, so that there were 2 guests inside. Then he took the 3rd guest to room number 2, the 4th guest to room number 3, and so on, until finally taking the 99th guest to room number 98. At the end he returned to room number 1 and took the 100th guest to room number 99, which was still vacant.

How could everybody get their own room?

The two people who were taken to room number 1 were guest 1 and guest 100. Thus, the 2nd guest ended up without a room.