09 December 2017

569. Divide into 4 areas

Easy Medium Hard Extreme


Add 10 matchsticks inside the layout above to create 4 areas equal in SIZE and SHAPE.

02 December 2017

568. Change to numerical equation

Easy Medium Hard Extreme


The above equation is not true. Move 2 matchsticks to change it to a valid numerical equation.

25 November 2017

567. The wood log problem

Easy Medium Hard Extreme


In a factory are 5 machines with each machine producing 5 pieces of compressed wood logs. The weight of each wood log is 500 grams.

However, one of the 5 machines is faulty and produces 5 logs with weight slightly more than 500 grams for each log. You do not know which machine is faulty and also not by how much.

Available in the factory is a digital single-tray scale. (not a two-tray balance scale) You are allowed to weigh as many logs as you wish at a time, but may use the scale only twice. How can you find the faulty machine?

Show Answer

STEP 1:
Place one log from each machine on the scale and weigh. Let's assume your answer is 2 510 grams. You now know the faulty machine produces 10 grams more for each log. (2 510 grams - 2 500 grams) But you still don't know which machine is faulty...

STEP 2:
Place the logs on the scale as shown above. The total weight is supposed to be 7 500 grams. (15 logs X 500 grams) Let's assume your answer is 7 530 grams which means there are 30 grams more than expected. (7 530 grams - 7 500 grams) Your faulty machine would therefore be machine 3. (30 grams / 10 grams) If machine 1 was faulty the weight would have been 7 510 grams, machine 2 would be 7 520 grams etc.

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18 November 2017

566. Matchstick Grid: Diagonal heads

Easy Medium Hard Extreme


This puzzle is similar to but different from number 500.

If you count the matchstick heads in each diagonal, vertical and horizontal row you will get to the numbers as shown above.

Your challenge is to rearrange the matchsticks to have:
- 4 heads in each row
- 4 heads in each column
- 8 heads in each diagonal row.

Your solution must still be a 2X2 matchstick grid.

12 November 2017

565. Move 2 to form 2 triangles

Easy Medium Hard Extreme


Easy, but people seem to struggle with this one...

Move 2 matchsticks to form only 2 triangles.

Show Answer

Nobody said the 2 triangles must be equal in size!

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11 November 2017

564. Triangle 3X3: Remove 6

Easy Medium Hard Extreme


TAKE AWAY 6 matchsticks to leave you with 6 triangles. All triangles must be equal in size.

05 November 2017

29 October 2017

562. Mathematical: 5 minus 1 is not 1

Easy Medium Hard Extreme


ADD 2 matchsticks to the layout above to make the equation true. Can you find both solutions?

28 October 2017

561. Pathway with 7 matchsticks revisited

Easy Medium Hard Extreme


This puzzle is similar to but different from Number 492.

7 matchsticks are used to form a pathway as shown above. The challenge is to start at a point, move in the direction of the matchstick heads and visit each of the 7 matchsticks only once.

A solution is not possible in the existing figure above, but by changing the direction of only 2 matchsticks it can be achieved. How would you do this?

Show Answer

Change the directions of matchsticks 1 and 5. The pathway is then from matchstick 1 to 7.

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22 October 2017

560. Find the next number

Easy Medium Hard Extreme


Think out of the box to solve this one!

FIND THE NEXT NUMBER... PLEASE

Show Answer

The number of letters in the different words of the question represent the numbers.

FIND = 4
THE = 3
NEXT = 4
NUMBER = 6
PLEASE = 6

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21 October 2017

559. Divide into 4 areas

Easy Medium Hard Extreme


Add 11 matchsticks inside the layout above to create 4 areas equal in size.

15 October 2017

558. Move 1 and still have 5 squares

Easy Medium Hard Extreme


There are 5 equal squares in the figure above. Move 1 matchstick so you still have 5 equal squares.

14 October 2017

557. Turn the direction

Easy Medium Hard Extreme


Your challenge is to turn the 4 matchsticks around so they are all facing the other way. The rules are:

1. Turn any 3 matchsticks in each move
2. You have 4 moves to achieve this.

08 October 2017

556. Letters and Numbers

Easy Medium Hard Extreme


Replace the letters with numbers to make the addition true. To help you to get going it can be revealed that L=8, A=9 and C=5.

Show Answer

   2 1 2 4
+ 9 3 7 8
----------
1 1 5 0 2

(By just looking at the leftmost letters it should be clear that F can only be 1)

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07 October 2017

555. Change the 3:4:5 ratio to 1:3:8

Easy Medium Hard Extreme


Place 6 matchsticks inside a 4X3 rectangle as shown above. The rectangle is divided into 3 parts in the ratio 3:4:5

Move only 1 matchstick inside the rectangle to change the ratio to 1:3:8

01 October 2017

554. Count the 4-sided figures

Easy Medium Hard Extreme


Ho many four-sided figures (squares and rectangles) do you count in the layout above?

Show Answer

There are 14 in total:

1. ABDF
2. ABCG
3. ICDE
4. GIEF
5. GCDF
6. HJKL
7. MNOP
8. QRST
9. HJZY
10. YZKL
11. UNVL
12. QXKW
13. YI2L
14. IZK2

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30 September 2017

24 September 2017

552. Change the ratios

Easy Medium Hard Extreme


Place 6 matchsticks inside a 3X3 square as shown above. The square is divided into 3 parts in the ratio 2:3:4

Move only 1 matchstick inside the square to change the ratio to 1:3:5

23 September 2017

551. Route map: 1- and 2-way roads

Easy Medium Hard Extreme


Shown in the puzzle above are one- and two-way roads. In total, how many different routes are there from point A to point J? You may only move in the direction of the matchstick heads and only travel on the same road once during the route.

Show Answer

There are 12 routes in total:

1. ABCFJ
2. ABEFJ
3. ABEHJ
4. ADEBCFJ
5. ADEFJ
6. ADEHJ
7. ADGHEBCFJ
8. ADGHEFJ
9. ADGHJ
10. ABEDGHJ
11. ABCFEDGHJ
12. ABCFEHJ

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17 September 2017

550. Move 3 to form 4 squares

Easy Medium Hard Extreme


There are 5 equal squares in the layout above. Move 3 matchsticks to have only 4 squares equal in size.

16 September 2017

549. Divide the square into 2 parts

Easy Medium Hard Extreme


5 matchsticks, placed horizontally and vertically, divide the square into 2 equal parts as shown above. The 2 parts are equal in shape and size. Another obvious solution would be 1 vertical and 4 horizontal matchsticks based on the same principle.

But there is another clever solution! In what other way can you place the 5 matchsticks inside the square to divide it exactly into 2 parts equal in shape and size?

Show Answer

AC is exactly the length of 3 matchsticks and BC exactly 4 matchsticks. Applying the Pythagoras's theorem you can proof that AB is exactly the length of 5 matchsticks:
(AB)² = (BC)² + (AC)²
(AB)² = 16 + 9
AB = √25
AB = 5

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09 September 2017

547. Pathway with 14 matchsticks

Easy Medium Hard Extreme


This puzzle is similar to numbers 492 and 502.

14 matchsticks are used to form a pathway as shown above. The challenge is to start at a point, move in the direction of the matchstick heads and visit each of the 7 matchsticks only once.

A solution is not possible in the existing figure above, but by changing the direction of only 1 matchstick it can be achieved. Which matchstick would you change and can you find the pathway?

Show Answer

The direction of matchstick 3 is changed.

One pathway is to start with matchstick 1 and end with matchstick 14.

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03 September 2017

546. Change to two

Easy Medium Hard Extreme


Somebody writes the above on a piece of paper. The answer is obviously 1, but what action can you perform to make the answer 2?

Show Answer

Turn the page upside down then 8-6 equals 2.

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02 September 2017

545. Divide into two identical pieces

Easy Medium Hard Extreme


Add 10 matchsticks to the square above to divide it into 2 pieces. The 2 pieces must be equal in size and shape.

Show Answer

There are also other variations of this solution.

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01 September 2017

544. Move 3 to form 2 squares

Easy Medium Hard Extreme


Move 3 matchsticks to form 2 squares.

An easy one, but how quickly can you solve it?