# MATH BRAIN TEASERS

### Fun Facts (Hints)

Mathematics has an extensive history in just about every culture or civilized society known to man. Listed below are some cool facts to get those math juices flowing:
• In 1852 mathematician JJ Sylvester established the "theory of algebraic invariants."
• In 1995 math great Andrew Wiles, proved "Fermat's Last Theorem."
• The first decimal number system is said to have been invented in Ancient Egypt around 5000BC.
• The Ancient Mayan civilization located in Central America is one of the only cultures in the recorded history of the world to use a place-value number system.
• The American Mathematical Society was formed in the late months of 1888 in New York.
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## 150 Pens Riddle

Hint:
She has misplaced 119 pens in total.
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Solved: 43%

## The Jug Full Of Beer

Hint:
First fill the 8 liters jug complete - 4, 8, 0
Fill the 5 liters jug with 8 liters jug - 4, 3, 5
Pour back the beer from 5 liters jug to 12 liters jug - 9, 3, 0
Pour the 3 liters from 8 liters jug to 5 liters jug - 9, 0, 3
Fill the 8 liters jug completely from 12 liters jug - 1, 8, 3
Fill the 5 liters jug from the 8 liters jug - 1, 6, 5
Pour the entire 5 liters jug back in 12 liters jug - 6, 6, 0

You have successfully split the beer into two equal parts.
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## A Large Box Of Money Riddle

Hint:
Just one, after which it will no longer be empty.
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Hint:
Fill the 5 gallon bucket all the way up. Pour it into the 3 gallon bucket until it is full. Empty the 3 gallon bucket. Pour the remaining 2 gallons into the 3 gallon bucket. Fill the 5 gallon bucket all the way up. Finish filling the 3 gallon bucket.
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Solved: 36%

## Feet In A Yard Riddle

Hint:
3.
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Solved: 56%

## Making Ten Riddle

Hint:
Yes it is possible in Roman Numerals. In Roman Numerals,
9 = IX
10 = X
11 = XI

Thus by removing one from 9, you are getting 10 and by removing one from 11, you are getting 10 again.
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Solved: 49%

## Zebras And Ostriches In The Zoo

Hint:
The number of Ostriches = 60 & The number of Zebras = 20
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Solved: 54%

## The Greater Dozen Riddle

Hint:
Six Dozen Dozen
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Solved: 65%

## A Rickety Bridge Riddle

Hint:
17 mins.

The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.

Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.

1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)

Total time = 2 + 2 + 10 + 1 + 2 = 17 mins
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Solved: 43%

## Seventeen Apples Riddle

Hint:
Make applesauce
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Solved: 57%

## 10 Boxes Riddle

Hint:
Let us simplify boxes by naming them from 1 to 10.
Now the trick here is to pick different number of balls from different boxes. So to simplify things, we will pick balls corresponding to box number.

Thus, pick 1 ball from Box 1, 2 balls from box 2, 3 balls from box 3 and so on. You will have 55 balls altogether. Now, put them all in the balance.

If all balls were weighing accurate 10 grams, the total weight of the 55 balls would have been 550 grams. But one of the box must have had the defective balls.

Suppose if the defective balls were in box number 2, then the total weight will be 2 grams less than 550. If the defective balls were in box 8, the total weight will be less than 8 grams from 550. In this way, you will be able to identify which box has the defective balls.
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Solved: 44%

## Eating Burgers Riddle

Hint:
18

More hours => more burgers.
More boys => more burgers.

The time become twice (3 hours / 1.5 hours).
Boys become six times (9 / 1.5).

Number of burgers = 2 * 6 * Original(1.5)
= 18
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Solved: 78%

## Bigger Upside Down Riddle

Hint:
A 6!
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Solved: 33%

Hint:
888 + 88 + 8 + 8 + 8 = 1000.
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Solved: 52%

## Green And Red Apple Trees Riddle

Hint:
The total was 40 Red apples and 32 Green apples.
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Solved: 63%

## Post Your Math Brain Teasers Below

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