Category Archives: Inductive reasoning

What’s next?


What comes next?****/*****

1,000, 1,000,000,000, 20, 100, 1, 4, 8, 3, ?

You can check your solutions here

New puzzles are published at least twice a month on Friday. Solutions are published after one or more weeks. You are welcome to remark on the difficulty level of the puzzles, discuss alternate solutions, and so on. Puzzles are rated on a scale of 1 to 5 stars.

This puzzle is a free translation of an AIVD (Dutch sister of NSA) puzzle in 2012.

Flags of countries (2)


Flags of countries (2)**/*****
178px-flag_of_el_salvador-svg
200px-flag_of_australia-svg
200px-flag_of_honduras-svg
flag_of_argentina-svg
flag_of_armenia-svg
flag_of_botswana-svg
flag_of_estonia-svg
flag_of_guatemala-svg
flag_of_israel-svg
flag_of_the_czech_republic-svg
flag_of_the_netherlands-svg

Which of the following three flags belongs to the group above:
flag_of_monaco-svg
flag_of_norway-svg
flag_of_sudan-svg

You can check your solutions here

New puzzles are published at least twice a month on Friday. Solutions are published after one or more weeks. You are welcome to remark on the difficulty level of the puzzles, discuss alternate solutions, and so on. Puzzles are rated on a scale of 1 to 5 stars.

Flags (1)


Flags of countries (1)***/*****
Look at these flags:
flag_of_belgium-svg
flag_of_the_peoples_republic_of_china-svg
flag_of_colombia-svg
flag_of_germany-svg
flag_of_hungary-svg
flag_of_lebanon-svg
flag_of_mali-svg
flag_of_romania-svg
flag_of_serbia-svg
flag_of_slovakia-svg

Which of the following three flags belongs in the above group:
a) 200px-flag_of_slovenia-svg
flag_of_guinea-bissau-svg
flag_of_bulgaria-svg

You can check your solutions here

New puzzles are published at least twice a month on Friday. Solutions are published after one or more weeks. You are welcome to remark on the difficulty level of the puzzles, discuss alternate solutions, and so on. Puzzles are rated on a scale of 1 to 5 stars.

Bongard problem (8)


The Russian scientist M.M. Bongard published a book in 1967 that contains 100 problems. Each problem consists of 12 small boxes: six boxes on the left and six on the right. Each of the six boxes on the left conform to a certain rule. Each and every box on the right contradicts this rule. Your task, of course, is to figure out the rule.

Bongard problem 8**
Bongard problem rule 11

You can check your solutions here

You can find more Bongard problems at Harry Foundalis site, and I intend to publish more problems in the future.

A new puzzle is published every Friday. Solutions are published after one or more weeks. You are welcome to remark on the difficulty level of the puzzles, discuss alternate solutions, and so on. Puzzles are rated on a scale of 1 to three stars.

Bongard problem (7)


The Russian scientist M.M. Bongard published a book in 1967 that contains 100 problems. Each problem consists of 12 small boxes: six boxes on the left and six on the right. Each of the six boxes on the left conform to a certain rule. Each and every box on the right contradicts this rule. Your task, of course, is to figure out the rule.

Bongard problem 7 rule 10 exercise

You can check your solutions here

You can find more Bongard problems at Harry Foundalis site, and I intend to publish more problems in the future.

A new puzzle is posted every friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.

Bongard problem (6)


The Russian scientist M.M. Bongard published a book in 1967 that contains 100 problems. Each problem consists of 12 small boxes: six boxes on the left and six on the right. Each of the six boxes on the left conform to a certain rule. Each and every box on the right contradicts this rule. Your task, of course, is to figure out the rule.

This weeks problem is from the hand of our daughter Margreet.

20160124_091224 20160124_091228

<pYou can check your solutions here

Coded germs


Pattern code germsOne of the type of puzzles taht has become a trademark of this blog are ‘coded patterns’

Which code goes to the question marks?

You can check your solution here

You are welcome to remark on the puzzle: its wording, style, level of difficulty. I love to read your solution times. Please do not spoil the fun for others by listing the solution. Solutions will be posted after one or more weeks.

The spy and the sentry


Castle DSC_0048A spy wanted to enter a castle, but this castle was guarded by a sentry. Only those who knew the password, were allowed to enter. The spy hid himself in the bushes near the guardhouse of the sentry, so that he could overhear the password.
The baker approached, and the sentry called:
‘If I say 12, what do you reply?’
‘6’
‘You may pass.’
The smith approached, and the sentry called:
‘If I say 6, what do you reply?’
‘3’
‘You may pass.’
The spy concluded: ‘I know enough’
With a long detour he went back, disguised himself as a grocer and approached the sentry. The sentry called:
‘If I say 4, what do you reply?’
‘2’
The spy was taken prisoner.
What should he have replied?

I would like to thank our daughter Margreet for passing on this nice problem, which she heard from Professor Jochem Thijs. Alas he did not reply to my question if he invented this puzzle or not. If he is not the inventor, and someone knows the original source, I would be grateful.

You can check your solution here

You are welcome to remark on the puzzle: its wording, style, level of difficulty. I love to read your solution times. Please do not spoil the fun for others by listing the solution.