Logic riddles

Flip switch number 1 and wait a few minutes. Flip switch number 1 back to its original position, and then immediately flip switch number 2.

Open the door. If the light is on, then switch number 2 controls it. If the light is off, then go and feel the bulb with your hand. If the bulb is hot, the switch number 1 controls it, and if the bulb is cold, then switch number 3, the one you did not touch, controls it.

What's the least number of chairs you would you need around a table to sit four fathers, two grandfathers, and four sons?

Answer

Four. The four fathers could be grandfathers and are definitely sons already.

Why is it better to have round manhole covers than square ones?

Answer

A square manhole cover can be turned and dropped down the diagonal of the manhole. A round manhole cover cannot be dropped down the manhole. So for safety and practicality, all manhole covers should be round.

You are in a room with 100 shooters, you kill one.
How many is left?

Answer

101
(you, 99 shooters alive, 1 shooter killed)

After teaching his class all about roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The only stipulation the teacher made was that the pen could not be lifted from the paper until the line was complete.

Answer

Draw an S in front of the IX and it spells SIX. No one said the line had to be straight :)

I am the owner of a pet store. If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

Answer

I have 3 cages and 4 canaries.