The river war

“It was during the Russian Civil War, ” Captain Abromovitch told his great grandchildren, “That I was ordered to take my ship, the Asbestos, down the river from Astrakhanitch to Cosmovitch. It was a valuable package I had to transport, and a dangerous mission as well, as the Tzarists still controlled Borovitch between Astrakhanitch and Cosmovitch. In Borovitch, the Tzarists held control of the Berilyum, a sistership of my Asbestos. Both had the same speed of 5 miles per hour on a lake without any current.”
He took a sip from his orange juice, and continued:
“They had a spy in Astrakhanitch, and this enabled the Berilyum to leave Borovitch to intercept me the minute I left Astrakhanitch with my Asbestos. Steaming upstream, of course the Berilyum went slower than my Asbestos steaming downstream, so we didnt meet in the middle between the two towns, but at a point closer to Borovitch than to Astrakhanitch. Having several soldiers on board, while I had none, they immediately seized my ship and brought us to Astrakhanitch.”

If the distance between Astrakhanitch and Borovitch is 20 miles, how long did it take the Tzarists to intercept the Asbestos?

You can check your solutions here

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 (3)

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.

Here is an example:

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.

The online exam

This week I’ve got a quickie for you.
Last week I took an online certification exam. It was an open book certifiction, and I was free to consult the website and course map as often and as long as I wanted. Some types of questions scored 3 points, others scored 5 points.

My result was:
You scored 201 points out of 223 total possible points.
You answered 45 out of 51 questions correctly.

How many 5-point questions and how many 3 point questions did I miss?

You can check your solutions here

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.

Inspector Simon Mart and the stolen toupet

Inspector Simon Mart looked out of the window of his familiar office room. What he saw was very familiar: nothing. Or, more precisely: the well known grey of London smog. It looked like a particular dense smog, as he could not even see the tree at the other side of the street, nor the pedestrians or traffic in the street below.

He would much, much rather have been at the sun drowned beaches of a tropical archipellego, but he was here back in London.
And he’d better get to work. He looked at the interrogation reports of the three criminals. The toupet of major Big Boaster had been stolen. The three criminals were all so rotten that none of the three could utter three sentences without speaking the truth more than once. Luckily, it had already been established that one of them was the thief.

Their interrogation reports:
Picking Pete: Rotten Ray is innocent. Thoughtless Theo is the thief. I am innocent.
Rotten Ray: To his dismay inspector Mart found that some thoughtless secretary had spilled coffee over this interrogation report, and it was completely unreadable.
Thoughtless Theo: Picking Pete is innocent. I am innocent. Rotten Ray is the thief.

Inspector Simon Mart got himself some tea from the coffee maachine and found that it tasted just like one can expect from a coffee machine: the tea tasted as coffee.
Still, he managed to conclude who the thief was. Can you?

You can check your solutions here

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.

The floor

I had to tile the floor of a room which was to 2 meters long and 2 meters wide. I had boards of 20 cm wide and either 1.60 or 1.80 meter long. How many boards do I have to saw so that I can cover the entire floor?

You can check your solutions here

The 4 cards

Before you are four cards on the table. The front side has an ‘A’ or a ‘B’ on it. The back has a ‘1’ or a ‘2’ on it. As you can see, two cards show their front side, and the other two cards show their back side.
A friend of mine thinks that on the back of every card with a ‘B’ there is a ‘2’.
Which card(s) do you turn to test his hypothesis?

This is not an original problem, and the source is unknown to me. I guess it is from somewhere in the twentieth century. I was recently reminded of it when thumbing through James Fixx “More games for the superintelligent”, a mensa publication. I hope to get back to this puzzle in a later post.

You can check your solutions here

Tectonics

The free Dutch daily newspaper Metro recently – I think it was in september – published a new type of puzzle calles tectonics.
The puzzle area usually is a rectangle, for example 4×5, which is subdivided into areas of size 1 to 5. An area of size 1 contains just the number 1, an area of size 2 contains the numbers 1 and 2, and so on, until an area of size 5 which contains the numbers 1, 2, 3, 4 and 5 exactly once.
A second rule is that the same number may never be adjacent: not horizontally, not vertically, and not diagonally.
Note that there is no rule that a number may appear just once in a row or column.

A complete filled tectonic may look like:

The puzzles in Metro are designed by Denksport, the largest puzzle publisher in the Netherlands. In the magazine shop I discovered a magazine with these puzzles.
Tectonic puzzle booklet can be ordered here. I think the order page is only in Dutch, and I’m not sure if you can mail order from abroad.

Nr 1)^*

Nr 2)^*

Nr 3)^**

You can check your solutions here, here, and here.

The publisher claims that these puzzles are a new international rage. That may well be true, but a quick search on “tectonic puzzles” turned up just puzzles on plate tectonics.

Digital matchsticks (4)

Move 2 matchsticks to get a correct equation:

You can check your solutions here

Bongard problems (2)

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.

Here is an example:

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.

Ages

In 2038 someone has an age which is exactly the sum of the digits of the year in which he was born.
In what year was he born?

You can check your solutions here