Lateral Thinking and Logic Puzzles

A hand-picked puzzle from each collection. Can you solve them?

The Camels

Four tasmanian camels traveling on a very narrow ledge encounter four tasmanian camels coming the other way.

As everyone knows, tasmanian camels never go backwards, especially when on a precarious ledge. The camels will climb over each other, but only if there is a camel sized space on the other side.

The camels didn't see each other until there was only exactly one camel's width between the two groups.

How can all camels pass, allowing both groups to go on their way, without any camel reversing?

Tasmanian Camels Puzzle

Drag a camel into the empty space. A camel may move forward one space, or jump forward over exactly one camel.

For best play, rotate your phone horizontally.
Start: L L L L _ R R R R
Hint:

Try solving the three Tasmanian camels problem first:

Solution:

Tasmanian Camels Solution

Four camels on each side swap places. Camels only move forward.

For best viewing, rotate your phone horizontally.
Start: L L L L _ R R R R
Click Next to begin.

The Missing Piece

The Missing Piece

The four partitions are exactly the same in both arrangements. Why is there a hole? Press Stop to drag the pieces yourself.

Where does this hole come from?
Click Stop to manually move these pieces around.
Hint:

This is not an optical illusion. If you print out the puzzle, cut out the pieces and rearrange them, you get the exact same dilemma.

Solution:

The gradient of the teal hypotenuse is different than the gradient of the red hypotenuse.


The Vegas Coin Flip Dilemma

You are in Vegas with $10,000. This is your entire bankroll.

The game is simple. I flip a fair coin. You may call heads or tails.

If you call correctly, your bankroll increases by 50%.

If you call incorrectly, your bankroll decreases by 40%.

My game has two unusual conditions:

1. You must bet your entire current bankroll each time you play.
2. You must decide now how many times you will play.

You may choose to play anywhere from 0 to 100 times.

How many times should you play?

Hint:

This is a classic economics problem that even economists get wrong!

Solution:

This is a terrible proposition for both you and me.

From my perspective, if I have a hundred people playing, I am losing 5% each round.

From your perspective, unless you are the lucky ten percent (~13.6%), you are losing 5% each round.

Here is the math behind it.

1. House perspective: expected value

Each round, the player’s bankroll is multiplied by:

Heads: ×1.5
Tails: ×0.6

Expected multiplier:

0.5 × 1.5 + 0.5 × 0.6

= 0.75 + 0.30

= 1.05

So the player gains 5% in expected value per round.

That means the house loses 5% in expected value per round.

After 100 rounds, expected player bankroll is:

$10,000 × 1.05^100 ≈ $1,315,013

So from the house’s perspective, this is a terrible game to offer.

2. Player perspective: compound growth

For the player, expected value is misleading because the whole bankroll is being compounded.

The compound-growth multiplier is the geometric mean:

sqrt(1.5 × 0.6)

= sqrt(0.9)

≈ 0.9487

So the typical player loses:

1 - 0.9487 = 0.0513

or about:

5.13% per round

That is why the player’s typical outcome is bad even though the expected value is positive.

3. After 100 rounds

If the player gets H heads and 100 - H tails, final bankroll is:

$10,000 × 1.5^H × 0.6^(100-H)

To finish ahead, they need:

1.5^H × 0.6^(100-H) > 1

Take logs:

H ln(1.5) + (100 - H) ln(0.6) > 0

Solve:

H > 55.749...

So the player needs at least:

56 heads out of 100

The probability of getting 56 or more heads with a fair coin is:

P(H ≥ 56) ≈ 13.6%

So:

About 13.6% of players win.
About 86.4% of players lose.


Lateral Thinking Puzzles
  • Preconceptions - Lateral thinking puzzles that challenge your preconceptions.
  • Fact - Lateral thinking problems that are based on fact.
  • Fanciful - Lateral thinking problems that require a little imagination to solve.
  • Semantics - Lateral thinking problems that require you to pay close attention to the exact wording of the problem.
  • Riddles - Wordplay and riddle-format puzzles.
Logic Puzzles
  • Very Easy - Logic problems that can be solved with a quick (or not so quick) flash of insight.
  • Easy - Logic problems that require some dedicated thinking to solve.
  • Difficult - Logic problems that can keep you thinking on a long commute.
  • Very Difficult - Extremely difficult problems that are great to take on a long flight.
  • Mathematical - Logic problems that require mathematics or logical algorithms.
Logic Puzzles
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