## 1. Water Jug Puzzle from Die Hard 3

1. Fill the five-gallon jug completely with water.
2. Pour three gallons of water from the five-gallon jug into the three-gallon jug.
3. This leaves two gallons of water in the five-gallon jug.
4. Pour the two gallons of water from the five-gallon jug into any container.
5. Empty the three-gallon jug completely.
6. Pour the two gallons of water from the other container into the three-gallon jug.
7. Fill the five-gallon jug completely with water again.
8. Pour water from the five-gallon jug into the three-gallon jug until it is full, which will take exactly one gallon of water from the five-gallon jug.
9. This leaves four gallons of water in the five-gallon jug.

Therefore, you can measure out exactly four gallons of water using only the five-gallon jug and the three-gallon jug.

## 2. Who is in the photograph

The person in the photograph is the man’s son.

The statement “that man’s father is my father’s son” means that the man in the photograph is related to the man who is looking at the photograph in some way. Specifically, it means that the man in the photograph is the son of the man who is looking at the photograph’s father. Since the man who is looking at the photograph says he has no brothers or sisters, and he is referring to the man in the photograph as “that man’s father,” it can be concluded that the man in the photograph is the son of the man who is looking at the photograph. Therefore, the person in the photograph is the man’s son.

## 3. Which is the correct switch

To determine which switch controls each light bulb using the given conditions, follow these steps:

1. Turn on the first switch and leave it on for a few minutes.
2. Turn off the first switch and turn on the second switch.
3. Enter the room.

Now, here’s what you will observe:

1st bulb: you must feel warm when you touch it.

2nd bulb: must be glowing as it’s switched on.

3rd bulb: you gonna feel nothing, as it’s left undone.

## 4. How can you measure 45 minutes using a rope

Here’s how you can measure 45 minutes using two ropes and a lighter:

1. Light both ends of the first rope and one end of the second rope at the same time.
2. The first rope will burn completely in 30 minutes, while the second rope will have burned halfway in 30 minutes.
3. At the 30-minute mark, light the other end of the second rope.
4. The remaining half of the second rope will burn completely in 15 minutes, which is the remaining time needed to reach 45 minutes.
5. When the second rope burns completely, 45 minutes will have passed.

So by burning the first rope for 30 minutes, and then lighting the second rope from both ends and measuring the time it takes to completely burn the second rope (which is 15 minutes), you can measure 45 minutes using these two ropes and a lighter.

## 5. 3 cuts to cut the round cake into 8 equal pieces

Step 1: Cut the cake into quarters (4 pieces) using 2 of the cuts – one horizontally down the centre of the cake and the other vertically down the center of the cake. This will leave you with 4 pieces (or slices) of cake.

Step 2: Then take all 4 pieces and arrange them in a stack that is 4 pieces high.

Step 3: Finally, you can just cut that stack of 4 pieces in half – using your third and final cut – and then you will end up with 8 pieces of cake!

## 6. A Room With No Windows

Look in the mirror, then at the wall and back at the mirror to see what you saw. Use the saw to cut the table in half and join the two halves to make a whole. Put the “hole” on the wall and climb out.

This is not a typical brain teaser with a logical reason. But it is a very popular one with a very unique answer.

## 7. Time

1:45. The man gave away a total of 25 cents. He divided it between two people. Therefore, he gave a quarter to two.

Envelope

## 9. The Prisoner

This is a classic paradoxical puzzle. There are different answers to this, but one possible answer is:

The prisoner can say: “You will hang me.”

If the statement is true, then the guards would be forced to shoot him, which would make the statement a lie. But if the statement is a lie, then the guards would be forced to hang him, which would make the statement true. Thus, no matter what the guards do, they cannot carry out their threat.

## 10. Balls and Balance

The minimum number of weighings required to determine which ball is the odd one out and whether it is heavier or lighter than the others is 3.

Here’s how it can be done:

Divide the 12 balls into three groups of 4 balls each. Weigh any two groups against each other. If the scales balance, then the odd ball is in the third group. If one side of the scales is heavier, then the odd ball is in that group.

Take the group of 4 balls that contains the odd ball and divide it into two groups of 2 balls each. Weigh these two groups against each other. If the scales balance, then the odd ball is one of the remaining two balls. If one side of the scales is heavier, then the odd ball is one of the two balls on that side.

Take the group of 2 balls that contains the odd ball and weigh them against each other. If one of the balls is heavier, then it is the odd ball and it is heavier than the other balls. If one of the balls is lighter, then it is the odd ball and it is lighter than the other balls.