You have a lighter and two fuses that take exactly one hour to burn, but they don’t burn at a steady rate. For example, one fuse could take 59 minutes to burn the first inch and then burn the rest of the fuse in the last minute.
How would you use these two fuses to measure 45 minutes?
Light the first fuse on both ends and the second fuse at only one end. When the first fuse burns out you know 30 minutes have passed. Light the other end of the second fuse and when it burns out, 45 minutes have passed.
A boat has a ladder that has six rungs. Each rung is one foot apart. The bottom rung is one foot from the water. The tide rises at 12 inches every 15 minutes. High tide peaks in one hour.
When the tide is at its highest, how many rungs are under water?
You are standing outside a closed door. On the other side of the door is a room that has three light bulbs in it. The room is completely sealed off from the outside. It has no windows and nothing can get in or out except through the door. On the outside of the room there are three light switches that control each of the respective light bulbs on the other side of the door.
Your assignment is to determine which light switch controls which light bulb. You are allowed to enter the room only once, and once you come out, you must be able to state with 100% certainty which light switch controls which light bulb.
Turn one light switch on, wait a few minutes, then turn it off and turn another light switch on. Go into the room and feel the light bulbs. The one that’s still warm is connected to the switch that you first turned on, the one that is on was the second switch you turned on, and the last bulb is controlled by the switch that you didn’t touch.
Two women apply for a job. They are identical and have the same mother, father and birthday. The interviewer asks, “Are you twins?” to which they honestly reply, “No”.
My daughter has as many sisters as she has brothers. Each of her brothers has twice as many sisters as brothers. How many sons and daughters do I have?
Four daughters and three sons. Each daughter has 3 sisters and 3 brothers, and each brother has 2 brothers and 4 sisters.
To figure it out mathematically, you could use the following two equations where G = the number of girls and B = the number of boys:
G – 1 = B
2(B – 1) = G
Solving for G gives you 4 and plugging that in to G – 1 = B gives you a B of 3.
The next number in the series counts the previous numbers. Thus the first number is 1, which is one 1, or 11. To describe 11, you have two 1’s, or 21. Now you have one 2 and one 1, so the next number is 1211. The solution is to continue describing the previous number using only numbers.