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The practice of mental exercising may also protect against collection of detrimental proteins in the brains of individuals who have Alzheimer's disease.
Studies show that vast levels of mental exercise are connected to better brain function throughout a person's lifetime.
Significantly for elderly people, partaking in highly complex mental exercises in later life is associated with a lower chance of developing dementia.
Solving complex brain riddles and other activities like journal writing are good ways to stimulate your mind daily.

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These brain teasers are very high in difficulty and have the solutions provided for when you feel like you've had enough.

Now you have a chance to prove just how clever you really are! Pit your brain against some of most challenging puzzles you can find, anywhere.

Also, be sure to check back regularly to continue to challenge yourself habitually with these great brain teasers. The more that you exercise your brain with puzzles and questions like the ones provided, the sharper your mind will be throughout each day.

## 3 Gallon Jug And 5 Gallon Jug

You have a 3-gallon and a 5-gallon jug that you can fill from a fountain of water.

The problem is to fill one of the jugs with exactly 4 gallons of water. How do you do it?

You've got to defuse a bomb by placing exactly 4 gallons (15 L) of water on a sensor. The problem is, you only have a 5 gallon (18.9 L) jug and a 3 gallons (11 L) jug on hand! This classic riddle, made famous in Die Hard 3.

The problem is to fill one of the jugs with exactly 4 gallons of water. How do you do it?

You've got to defuse a bomb by placing exactly 4 gallons (15 L) of water on a sensor. The problem is, you only have a 5 gallon (18.9 L) jug and a 3 gallons (11 L) jug on hand! This classic riddle, made famous in Die Hard 3.

Hint:

Fill the 5-jug up completely. There will be, of course, 5 gallons in the 5-jug. You must fill all the gallons up to the top, otherwise you don't actually know how much you have.

Use the water from the 5-jug to fill up the 3-jug. You're left with 3 gallons in the 3-jug and 2 gallons in the 5-jug.

Pour out the 3-gallon jug. You're left with nothing in the 3-jug and 2 gallons in the 5-jug.

Transfer the water from the 5-jug to the three jug. You're left with 2 gallons in the 3-jug. And nothing in the 5-jug.

Fill up the 5-jug completely. You now have 2 gallons in the 3-jug and 5 in the 5-jug. This means that there is 1 gallon (3.8 L) of space left in the 3-jug.

Use the water from the 5-jug to fill up the 3-jug. Fill up the last gallon of space in the 3-jug with the water from the 5-jug. This leaves you with 3 gallons in the 3-jug, and 4 gallons in the 5-jug.

Fill the 3-jug completely with water. You now have 3 gallons (11.4 L) of water.

Transfer this water into the 5-jug. You now have nothing in the 3-jug, and 3 gallons (11.4 L) in the 5-jug.

Re-fill the 3-jug with water. You now have 3 gallons (11.4 L) in the 3-jug and 3 gallons in the 5-jug.

Fill the 5-jug with water from your 3-jug. You now have 1 gallon (3.8 L) in the 3-jug and 5 gallons (18.9 L) in the 5-jug. This is because, in the last step, you only had 2 gallons (7.6 L) of space left over, so you could only pour 2 gallons.

Pour out the 5-jug and refill it with your 1 gallon. You now have nothing in the 3-jug and 1 gallon in the 5-jug

Fill up the 3-jug. You now have 3 gallons (11.4 L) in the 3-jug and 1 in the 5-jug.

Transfer the 3 gallons (11.4 L) of water into the 5-jug to end up with 4 gallons (15.1 L). Simply pour over your three gallons into the 5-jug, which only had 1 gallon (3.8 L) in it previously. 1+3=4, and a successfully defused bomb.

YES NO

Use the water from the 5-jug to fill up the 3-jug. You're left with 3 gallons in the 3-jug and 2 gallons in the 5-jug.

Pour out the 3-gallon jug. You're left with nothing in the 3-jug and 2 gallons in the 5-jug.

Transfer the water from the 5-jug to the three jug. You're left with 2 gallons in the 3-jug. And nothing in the 5-jug.

Fill up the 5-jug completely. You now have 2 gallons in the 3-jug and 5 in the 5-jug. This means that there is 1 gallon (3.8 L) of space left in the 3-jug.

Use the water from the 5-jug to fill up the 3-jug. Fill up the last gallon of space in the 3-jug with the water from the 5-jug. This leaves you with 3 gallons in the 3-jug, and 4 gallons in the 5-jug.

Fill the 3-jug completely with water. You now have 3 gallons (11.4 L) of water.

Transfer this water into the 5-jug. You now have nothing in the 3-jug, and 3 gallons (11.4 L) in the 5-jug.

Re-fill the 3-jug with water. You now have 3 gallons (11.4 L) in the 3-jug and 3 gallons in the 5-jug.

Fill the 5-jug with water from your 3-jug. You now have 1 gallon (3.8 L) in the 3-jug and 5 gallons (18.9 L) in the 5-jug. This is because, in the last step, you only had 2 gallons (7.6 L) of space left over, so you could only pour 2 gallons.

Pour out the 5-jug and refill it with your 1 gallon. You now have nothing in the 3-jug and 1 gallon in the 5-jug

Fill up the 3-jug. You now have 3 gallons (11.4 L) in the 3-jug and 1 in the 5-jug.

Transfer the 3 gallons (11.4 L) of water into the 5-jug to end up with 4 gallons (15.1 L). Simply pour over your three gallons into the 5-jug, which only had 1 gallon (3.8 L) in it previously. 1+3=4, and a successfully defused bomb.

*Did you answer this riddle correctly?*YES NO

## Borrow $50 From Mom And $50 From Dad Riddle

I borrowed $50 from mom and $50 from dad to buy a bag costing $97. After the purchase, I had $3 left. I returned $1 to dad and $1 to mom, and reserved $1 for myself. I now owe $49+$49=$98 plus the $1 I reserved for myself, which is $99. Where is the missing $1?

Hint:

Total Money taken = $100($50+$50)

Now,

Bag's Price = $ 97

Remaining Amount = $100 - $97

= $ 3

Returned = $ 1 + $ 1

=$2

In pocket = $1

Total money owed = $100- ( Returned amount)

= $98( Bag's amount and reserved amount)

So, it was a calculation mistake.

YES NO

Now,

Bag's Price = $ 97

Remaining Amount = $100 - $97

= $ 3

Returned = $ 1 + $ 1

=$2

In pocket = $1

Total money owed = $100- ( Returned amount)

= $98( Bag's amount and reserved amount)

So, it was a calculation mistake.

*Did you answer this riddle correctly?*YES NO

## A Dash At 20 And A Dot At 60

Hint: It's not a clock.

## Hard To Find Riddle

Hint:

## Difficult To Trick Python Riddle

Hint:

Because they only really have three main thoughts; 'Can I mate with it, will it hurt me or can I eat it?'

YES NO

*Did you answer this riddle correctly?*YES NO

## Hangs On The Wall And Falls Riddle

Hint:

## Shoe Man Whistle

Hint:

The third equation has a term with a pair of whistles. The last line involves a single whistle.

Furthermore, the man in the second and third lines are wearing a whistle, but the man in the last line is not wearing a whistle. Presumably the value of the whistle should be accounted for to get the correct answer.

The pictures can be translated into the following equations:

shoes + shoes + shoes = 30

shoes + (man + whistle) + (man + whistle) = 20

(man + whistle) + 2(whistles) + 2(whistles) = 13

shoes + (man) x (whistle) = ?

From the first equation we can solve for the shoes value:

shoes + shoes + shoes = 30

3(shoes) = 30

shoes = 10

We can then solve the second equation for the (man + whistle) value:

shoes + (man + whistle) + (man + whistle) = 20

10 + 2(man + whistle) = 20

2(man + whistle) = 10

man + whistle = 5

Then we solve the third equation for the whistle:

(man + whistle) + 2(whistles) + 2(whistles) = 13

5 + 4(whistles) = 13

4(whistles) = 8

whistle = 2

We also need to solve for the value of the man:

man + whistle = 5

man + 2 = 5

man = 3

Now we can evaluate the final expression, remembering the order of operations that multiplication should be evaluated before addition:

shoes + (man) x (whistle) = ?

10 + 3 x 2

= 10 + 3 x 2

= 10 + 6

= 16

YES NO

Furthermore, the man in the second and third lines are wearing a whistle, but the man in the last line is not wearing a whistle. Presumably the value of the whistle should be accounted for to get the correct answer.

The pictures can be translated into the following equations:

shoes + shoes + shoes = 30

shoes + (man + whistle) + (man + whistle) = 20

(man + whistle) + 2(whistles) + 2(whistles) = 13

shoes + (man) x (whistle) = ?

From the first equation we can solve for the shoes value:

shoes + shoes + shoes = 30

3(shoes) = 30

shoes = 10

We can then solve the second equation for the (man + whistle) value:

shoes + (man + whistle) + (man + whistle) = 20

10 + 2(man + whistle) = 20

2(man + whistle) = 10

man + whistle = 5

Then we solve the third equation for the whistle:

(man + whistle) + 2(whistles) + 2(whistles) = 13

5 + 4(whistles) = 13

4(whistles) = 8

whistle = 2

We also need to solve for the value of the man:

man + whistle = 5

man + 2 = 5

man = 3

Now we can evaluate the final expression, remembering the order of operations that multiplication should be evaluated before addition:

shoes + (man) x (whistle) = ?

10 + 3 x 2

= 10 + 3 x 2

= 10 + 6

= 16

*Did you answer this riddle correctly?*YES NO

## Playing With A Book Riddle

My son was playing with a book and tore out pages 7, 8, 100, 101, 222, and 223.

How many pages were torn out?

How many pages were torn out?

Hint:

10. Remember pages of a book are double-sided.

7+8, 99+100, 101+102, 221+222, 223+224s.

YES NO

7+8, 99+100, 101+102, 221+222, 223+224s.

*Did you answer this riddle correctly?*YES NO

## The Older Twin Brother

Hint:

It's all because the clocks went back. Samuel Peterson was born on 1.39am on Sunday, November 6. His brother Ronan, meanwhile, was born 31 minutes later, but by then daylight saving hours had ended, and the clock was turned back one hour.

So while Ronan was in a sense born at 2:10 am on November 6, his official time of birth is actually 1:10 am.

YES NO

So while Ronan was in a sense born at 2:10 am on November 6, his official time of birth is actually 1:10 am.

*Did you answer this riddle correctly?*YES NO

## Tell Us What You See

Have a look at the pic and tell us what it is. It definitely is something btw and once you know it's super obvious!

Still can't see it? Look harder!

Still can't see it? Look harder!

Hint: Stare at the white contrast.

## Post Your Hard Brain Teasers Below

Can you come up with a cool, funny or clever Hard Brain Teasers of your own? Post it below (without the answer) to see if you can stump our users.