Missing Dollar

Tom, Dick, and Harry each paid 10 dollars for a room at the hotel. When the manager found out, he told the desk clerk that Tom, Dick, and Harry were friends of his and they should be charged only $25.

The desk clerk gave the bell boy $5 and told him to return it to Tom, Dick and Harry. The bell boy, however, decided to give them only three dollars and keep two for himself.

hotel porter

If Tom, Dick and Harry each received $1 back, then that means they only paid $27 for the room. With the $2 the bell boy has in his pocket, the total is $29.

What happened to the missing dollar?

Water & Wine Glasses

Start with two glasses, one filled with water, the other filled with wine.
wine glasses
A spoonful of wine is taken from the wine-glass and stirred into the water-glass, then a spoonful is taken out of the water-glass and returned to the wine-glass. The operations are repeated.

Is there more water in the wine-glass than there is wine in the water-glass or the other way round?

Time Bomb

You have two matches, and two fuses (pieces of string) which each burn for 30 seconds, and a bomb which must go off exactly 45 seconds after you light the fuse.
time bomb
How do you determine exactly 45 seconds, using just these two matches and two fuses?

Note: Cutting one fuse in half won’t solve the problem because the fuses are of different thicknesses, and you can’t be sure how long any cut piece will burn.