18 August 2018

A weekend puzzle

In a class there were 40 students with roll numbers 1 thru 40. One day, the teacher got them all to sit around in a circle sequentially in the order of their roll numbers (1 thru 40). (Of course 40 sat next to 39 on one side and 1 on the other). She then gave a wand to student number 1. What the student had to do is turn towards the next student (which would be #2) and tag him/her with the wand. Upon tagging, the tagged student steps back and is out of the game and the wand is then handed to the next student – which would be student #3 in this case

Now student #3 does the same thing – tags student #4 who steps back and is out of the game and then the wand is handed to #5.

This keeps going on and on (in circles) till only one student is left.

Can you figure out which student was the last one left?

5 August 2018

Puzzle: The horse race problem

A friend of mine from Australia sent me this problem yesterday. It turns out to be a very interesting puzzle. See if you can get it. Feel free to send in your answers or attempts in the Comments section and I will try to respond.

In a horse race, 25 horses show up to win the gold, silver and bronze medals. Unfortunately for the organizers, there are only 5 tracks available – which means you can race only 5 horses at a time. The owners/jockeys agree that their horses will have to run multiple times to decide the first, second and third ranks. You can assume that a horse can run any number of times and always retains the same speed anytime it runs.

Here is the question: What is the minimum number of races you have to have to decide the gold, silver and bronze medalist?

10 June 2018

Puzzle: Learning about new countries

When I visited Mongolia this time, Roger introduced me to a book “Tuva or Bust”. If you have not read that book, chances are you would not know that there used to be a country called Tannu Tuva (kind of northwest of Mongolia). Or that the Noble prize winning physicist Richard Feynman never fulfilled his wish to visit that country in spite of years and years of efforts.

That got me thinking about how little I knew about countries. Actually, my knowledge of countries is pretty much stuck with what I had learnt (and how the world looked) during my school days – so let’s say mid 80s. Even then, I was terrible with countries from Africa.

After coming back from Mongolia though, I did make some effort to learn about the new countries that have formed in the last two decades or so. Previously, I could not even place them in the world map. Now I can. I am still struggling with the names of their capitals though.

I cannot give you this puzzle without ruling Sharmistha Kolay out of this game. She is a whiz kid when comes to geography. Not only can she name each and every country by continent and place them in a world map, she can name their capitals and …. get this… tell you what their flag looks like. I have never met anybody like her.

So here is the puzzle… I will name some newly formed countries… and you will have to name their capital. Try it by yourself. And then Google them up. How many did you get?

A. Countries that formed when USSR broke up:

-> “The Stans” in Asia
1. Tajikistan
2. Turkmenistan
3. Kyrgyzstan
4. Uzbekistan
5. Kazakhstan

-> Between the Caspian Sea and the Black Sea
6. Azerbaijan
7. Armenia
8. Georgia

-> In Europe
9. Ukraine
10. Moldova
11. Belarus
12. Latvia
13. Lithuania
14. Estonia

B. Countries that formed when Yugoslavia broke up:

15. Serbia
16. Bosnia Hercegovina
17. Montenegro
18. Macedonia
19. Kosovo
20. Slovenia
21. Croatia

C. Other new countries

-> Africa
22. South Sudan
23. Eritrea
24. Namibia

-> Asia
25. East Timor (Timor-Leste)
26. Palau

-> Europe
27. Slovakia
28. Czech Republic

BTW, I could not even reach the one-third mark!!! How many did you get?

Finally for the bonus question… and maybe we will open this up to Sharmistha even… Have you heard of a country called the Republic of Artsakh? Look it up!!

27 April 2018

An interesting problem to solve…

Imagine this… I am on a 15 hour flight from Doha to Atlanta. There is a TV screen with a lot of movies but I do not watch movies. There are my favorite shows like Big Bang Theory, Friends etc but how many times can you see the same 10 episodes? Remember, I had to take a 15 hour flight going to Doha too. And I do this multiple times a year.

So, I was lazily looking into the progress of the plane on the map of the globe. It was showing on the globe where we were and our trajectory. Notice the picture on the top half. As you can see, we were somewhere around the New Foundland area in Canada.

Here is the problem:
I was trying to ascertain roughly where the north pole was in that map. Just to see how close did we go to the north pole. The problem is in this map, all of Greenland and the Arctic area is shown as one white blob.

I also want to let you know that the screen is a smart one like you have in iPad. You can use one finger to go left and right and using two fingers, you can make the globe rotate (on any axis – depending on how you swipe both fingers). As an example, I used my two fingers and slid them up and a little to the left. As you can see in the picture in the lower half, the world rotated on a horizontal axis and rotated to the left. You can notice how North America moved up and then the North pointer in the compass turned by 90 degrees.

The point is, using the two fingers, you can turn the globe on any axis as you want (going thru the center of the earth).

Using this, can you pinpoint where the North Pole is?

21 February 2018

Another puzzle. Arranging digits

Do not write the answer in the Comments section. If you get the answer, simply message me on FB or write in the Comments section that you got it (without actually giving away the answer).

Can you come up with a 8 digited number where the digits are 1,1,2,2,3,3,4,4 and the following are true:
There are exactly 4 digits between the two “4”s in the number.
There are exactly 3 digits between the two “3”s in the number.
There are exactly 2 digits between the two “2”s in the number.
There is exactly 1 digit between the two “1”s in the number.

So, 12344321 cannot be an answer since there are 6 digits between the “1”s, 4 digits between the “2”s etc etc etc.

What is the number? (Hint: There are two answers)

9 February 2018

Puzzle time!!

Sitting at the motorbike center (bike getting serviced), I am bored enough to see if I can bore you with one more puzzle to get the weekend rolling ….

There is a contest to judge the smartest couple of them all. Teams of husbands and wives show up for the contest and are soon read out the rules…

Each couple will be taken to a separate room by two officials. Each room will have two tables in diagonally opposite corners. The couple will be separated in the room and asked to go sit at the two tables in the two corners with their backs to each other. From that distance, they will not be able hear or see what is going on in the other table. Under no circumstances can any of the couple utter any sound. If they do, they would be automatically disqualified. Next to each table sat one of the two officials.

The husband and the wife will be given a dice (all dice are perfect dice – one sixth probability for each side). At the sound of a large gong, they will independently roll their own dice on their own table. And note whether they have an even face up or an odd face up. (Odd means 1, 3 or 5). Now, on a piece of paper, each have to write what they think came up on the OTHER table – odd or even. Once both have written their guesses, the two officials will shout out what was written.

If at least one of them guessed correctly about the other table, they continue. If both got it wrong, they will be escorted out of the room and eliminated from the event.

The last couple standing (actually sitting at their tables 🙂 ) wins the event.

So those were the rules.

After all the rules were explained, the officials allowed each couple to talk for a few minutes in case they wanted to come up with a plan and then were escorted to their rooms for the competition to begin.

The smartest couple had devised a way such that they would always win. What strategy did they use?

Note that this is not a trick question like whispering or passing hand messages etc. They were really smart and came up with a way to never get escorted out.

If you know the answer / figured it out, please send me a personal message. I will respond there and also announce your name in the common forum.

29 January 2018

Here is a somewhat trickier puzzle – Catching a mouse

There are five adjoining rooms – linearly arranged (from left to right). You know there is a mouse in one of those rooms. You also know that the mouse, every night moves to the adjoining room – either left or right. It does not stay in the same room two days in succession – meaning it will definitely move. However, it is completely random whether it will go left or right – unless, of course it is in one of the end rooms in which case, it has to go to the other side.

Now, you are allowed to open any one random room in the morning. If the mouse is there, you can trap it and catch it. But if you do not find it, you are not allowed to go to other rooms. You have to come back the next day and open any room you want again (including the one you opened to today – totally your choice).

What is the strategy you will use (of targeting rooms to open each morning) to eventually catch the mouse?

29 January 2018

Merry Go Round Puzzle

This can be a very simple problem or a very confounding problem depending on the approach you take to solving it…

In a merry go round for kids in the mall, a kid rider observed “Two thirds the number of kids ahead of me added to three eighths the number of kids behind me add up to the total number of kids on this merry go round”.

How many kids were there in the merry go round?

28 September 2017

Presidential Trivia

To distract all my USA FB friends voicing their strong opinions for or against our current President’s tweets/statements on NFL players “taking the knee” (ha ha), here are some Presidential trivia questions. Hope both sides of the debate can work together to find the answers….

1. I was stunned to find out recently who our first President to have been born in a hospital was. Want to take a guess?

2. George Washington, of course, was our first President. Did you know that in both his terms, he was voted unanimously to be the President? Not a single electoral college of any party voted against him. Here is the question – which party did he represent in those two elections?

3. Kennedy, as we know was the youngest person to have been elected President. (Technically, Teddy Roosevelt became President when he was younger than Kennedy but that was not thru an election – previous President was assassinated). How about the oldest President to have been elected?

4. There has been only one President in the history of US who was a confirmed bachelor. Who was it?

5. On the other hand, there was another bachelor who was elected the President. And he married his sweetheart in White House while he was the President. In fact, even had his daughter born in the White House. Who was it?

6. We know many Presidents who have held the position multiple times. Almost always consecutively. (Of course, after Franklin Roosevelt’s 12 years of Presidency, there was a law promulgated that put a cap to 2 terms only). In fact, in the recent past, Obama, George W, Bill Clinton have been all 2 term presidents. There has been only one President who had 2 terms but not consecutively. He won, then lost a rebid and then won again the next time. Making him the only President who has 2 separate numbers for himself(like George HW Bush was 41 and his son was 43…). Who was it?

7. We have all heard about the crazy schedule of Presidents. President Obama, for example, wore the same color shirt and trousers to avoid wasting time in the morning in selecting clothes. On the other hand, there was a President that woke up every morning at 5AM only to practice piano for 2 long hours!! Who was it?

8. Being a President and being the Chief Justice of the Supreme Court are two of the highest positions in US (in fact they are the highest positions in two of the three branches – Executive, Legislative and Judiciary wings). There was one President that has the distinction of being both (of course – at different times). Do you know who it is?

9. A sitting President was once pulled over and arrested for going too fast (eventually fined too). Who was it? I will give you a hint – he was crossing the speed limit while riding a horse!!

10. There was one fortunate President who survived two consecutive attempts to assassinate him within a space of 17 days – and I say fortunate since he survived both attempts. Here is the crazy thing. Both were attempted by women. In fact, those were the only instances of a woman ever attempting to assassinate a sitting US President. Who was that President?

Bonus question:
By most accounts, Anne Royall was the first female journalist of this country. She had tried, for months, to score the first ever woman conducted interview of a US President. The President just would have nothing if it. Anne came up with a devious plan. She had found out that the President regularly swam in the Potomac early mornings. In the nude!!! So, she simply snuck up on him one morning while he was in the river, gathered all his clothes and sat on them till he would agree to an interview! Who was that hapless President (no doubt he would consider himself lucky to be in the pre-selfie era 🙂 )

31 August 2017

Some random facts that I have learnt over the years…

Here are five of them:

1. Do you know how the Romans whitened their teeth? Believe it or not, they used urine. Now, the chemically oriented ones among you obviously have figured out that it should work. And it does. But, please, please, DO NOT try this at home.

2. Since we dealt with the Romans, let’s talk about the Greeks. And their drinking. Drinking wine. I bet you that brings up images of Greeks drinking themselves silly thru the night in drinking orgies. Well, here is the deal, The Greeks drank wine. A lot of that. But they despised anybody who got overly drunk. You know what they did? They mixed what you and I call wine with water – one part of wine to five parts of water!! I can see all my wine enthusiast friends grimacing 🙂

3. Can you imagine being struck by lightning? How about twice and living thru it? How about thrice and still living. Park Ranger Sullivan was struck seven times – SEVEN times – by lightning while on duty in park. You know how he eventually died? Self inflicted gun wound. Apparently while cleaning his guns!!

4. How long for light to emanate from the core of the sun to reach the earth. I know many of you are going eight and a half minutes. But that is the time taken for light to travel from the surface of the sun to the surface of earth. Actually a photon takes thousands of years to get from the center of the sun to the surface of the sun and then another eight and a half minutes to get to earth!

P.S. Does that we are really living in the past? 🙂

5. Ratio of humans to ants. Want to take a guess?
There are 1.6 million ants to every human being!!
And all those ants put together – will weight about all the humans put together!!

Hope you enjoyed these. My friend from i2 – Dev Ghoshal – had once accurately remarked: I focus on inconsequential data 🙂