Deduction 3 - Puzzle Prime

Died on the Fourth of July

Section: Brain Teasers Category: Deduction

Difficulty: Medium

During a trivia night, the following question appeared:

“Among the first five US presidents, Washington, Adams, Jefferson, Madison, and Monroe, there were 3 who died on the fourth of July. Can you guess which ones?”

After nobody answered the question, the following hint was given:

“These three presidents were consecutive ones.”

Then, all contestants immediately managed to answer the question. Can you?

SOLUTION

Because of the way the question was worded, it was clear that the fifth president, James Monroe, was one of them. Otherwise, the trivia question would have been “among the first four US presidents” instead of “among the first five”. Since the three presidents that died on fourth of July were consecutive ones, they were Jefferson, Madison, and Monroe.

Unknown Author February 16, 2023

2 Comments

Limbs

Section: Brain Teasers Category: Deduction

Difficulty: Advanced

Partition the grid into disjoint “creatures”, according to the following rules:

Each creature is defined as a shape of 4 connected branches that are each 1 cell wide.
For each creature, one of the branches ends up with a HEAD (always clued) and the other three branches end up with LIMBS (whenever clued, their directions matter).
A creature can never occupy a 2×2 region of cells and can never touch itself.

Examine the first example, then solve the other three puzzles.

SOLUTION

The solutions are shown below.

Blaž Urban February 10, 2023

0 Comments

Get the Car

Section: Brain Teasers Category: Deduction

Difficulty: Medium

If you make a CORRECT statement, you will get either a lollipop or a chewing gum. If you make a FALSE statement, you will get either a chocolate or a car. What statement should you make in order to get the car?

SOLUTION

You should say “I will receive a chocolate”. This statement cannot be correct, since if it was, you would get a lollipop or a chewing gum, not a chocolate. Therefore, you will get the car.

Raymond Smullyan January 22, 2023

0 Comments

Elemental Puzzles

Section: Brain Teasers Category: Deduction

Difficulty: Medium

Below each of the following Venn diagrams there are seven tiles consisting of two letters. Place each tile in a different region so that the four tiles in each circle can be rearranged to solve the corresponding clue.

SOLUTION

The solutions are shown below.

Greg Wall January 7, 2023

0 Comments

Real Word Gogen Puzzle

Section: Brain Teasers Category: Deduction

Difficulty: Advanced

Add the 25 letters between A and Y to the grid below. Each one should appear exactly once. When you have finished, you must be able to spell the following words moving horizontally, vertically or diagonally around the grid:

AXIOM, BANQUET, CHOMP, FAWN, JOY, LURKED, RUN, STY, VYING

SOLUTION

The solution is shown below:

Andrew Reid December 28, 2022

3 Comments

Leave No Squares

Section: Brain Teasers Category: Deduction

Difficulty: Hard Tags: Matchsticks

How many matchsticks do you need to remove so that no squares of any size remain?

SOLUTION

Nine matchsticks are enough, as seen from the solution below.

To see that eight matchsticks are not enough, notice that removing an inner matchstick reduces the number of 1×1 squares at most by 2. Since there are 16 such small squares, in order to get rid of them all, we need to remove only inner matchsticks. However, in this case, the large 4×4 square will remain.

Unknown Author December 19, 2022

0 Comments

Hexado Puzzles

Section: Brain Teasers Category: Deduction

Difficulty: Advanced

Place arrows along the hexagon edges so that the number of arrows pointing to each hexagon equals the number of dots inside, adhering to the following rules:

Arrows cannot be touching.
Arrows cannot be placed on dashed edges.

SOLUTION

The solutions are shown below.

Dr. DJ Upton December 4, 2022

0 Comments

1 to 8 on a Cube

Section: Brain Teasers Category: Deduction

Difficulty: Medium

Place the numbers from 1 to 8 on the vertices of a cube so that the sum of the four numbers on every face is the same.

SOLUTION

The solution is shown below:

Unknown Author October 16, 2022

3 Comments

No Three Pawns on a Line

Section: Brain Teasers Category: Deduction

Difficulty: Medium

How many pawns can you place at most on a chess board so that no three pawns lie on a single line, horizontal, vertical, or diagonal?

SOLUTION

Since there are 8 rows on the chess board, if you place more than 16 pawns, then there will be at least 3 that lie on a single horizontal line. An example with 16 pawns is shown below: