26 September 2015

Puzzle: Boarding a plane

Last morning, I was having a rather humorous email exchange with some of my friends from my previous job when one of them, Gasan, sent a very interesting puzzle. This is not that simple. What is surprising is his kids got this problem as a homework problem. Also Raj let me know that the answers are all over the internet. So, if you want to exercise your brain, do not Google it up. After you have given it whatever time you want to give, feel free to look up the answer.

Meanwhile, just to show how much fun we had as a team – or rather the team had at my expense, I am going to copy Gasan’s articulation of the problem as is…

A line of 100 airline passengers are waiting to board a plane. They each hold a ticket to one of the 100 seats on the flight. (for some reference, let’s say that the nth passenger in line has a ticket for the seat number n.)
Unfortunately, the first person in line is a crazy bald headed guy named Rajib, and will ignore the seat number on their ticket, picking a random seat to occupy. All the other passengers including Gasan, Chris, Sunjay, even Raj and Karthik are quite normal, and will go to their proper seat unless it is already occupied. If it is occupied, they will then find a free seat to sit in, at random.
What is the probability that the last (100th) person to board the plane will sit in their proper seat (#100)?

20 September 2015

Poet unknown…

“Aap gairon ki baat karte hain
Humne to apne bhi aazmayen hain
Log kaaton se bachke chalte hain,
Humne to phoolon se zakhm khaayen hain!!”

Roughly translated…

“You keep complaining about strangers
I have tried my own loved ones too
People try to stay clear of thorns
And I have been hurt by flowers!!”


17 September 2015

A simple but elegant puzzle

Five friends at the gym came upon the new weighing machine recently installed there. They decided to take their weights in pairs (two at a time). The five of them can have ten pairings. They found the weights to be 259, 251, 264, 281, 268, 242, 257, 266, 253 and 275 pounds.
From this can you find out what were the individual weights of the friends?

If you are reading this on FB, message me if you have found the answers and your method.

14 September 2015

A different kind of local train passenger

You probably have heard me saying this often before – I am always struck by the difference in the attitude of people as they age between India and US. While generalization of any sort is fraught with danger – and I have certainly seen a few strong exceptions – but by and large, I tend to believe the following: compared to the country I live in (US), folks in the country where I was born and visit often (India), people, as they age tend to have a far less physically active life. And also seem to complain more. I would certainly put my parents in that category. But as I said, I run into exceptions too. I get inspired by those exceptions and that is why I write about them.

Such an encounter happened yesterday. I had a few hours left before I had to say bye to my parents and leave for the airport. I was aware that a gentleman that I wanted to meet for some time was going to be in Kalyani (small town where my parents live now) on that day. He is the father of a friend of mine in Atlanta – Nachiketa. I figured it would be good to go and say Hi to him. I was sure he would be thrilled to know that I live in the same place as his son does and we can talk about a few things. Also, my elder daughter and his youngest granddaughter are very close friends.

Before long, my brother and I were knocking on the door of what seemed to be the right address. There was no response. I pushed the door and it opened. I raised my voice to ask if anybody was inside. Soon, a very elderly gentleman came out. I introduced myself as his son’s friend from Atlanta and that I live in Kalyani too. Now, the last part was not correct at all but I was afraid that he would jump to all sorts of wrong conclusions when somebody comes unexpectedly from Atlanta saying that he knows his son. Eventually I corrected myself and let him know that my parents live in Kalyani but I personally have never done so.

In any case, I had bargained for half an hour of pleasantries – after all he was 86 years old and take leave of him. Turned out it went for over an hour and if I did not have a flight to catch, I could have sat for another hour. What had my jaw drop is that this gentleman – as I said 86 years old – takes the 5 o’clock local train every Sunday from Kolkata (where he lives) and comes to Kalyani where he has a house. He spends the day there and then next day goes to another town and teaches Post Graduate students in a college there. At 86 years old!! He travels in local trains (only people from Kolkata area will know what it is like to travel in crowded local trains)!! And teaches in a college!! I found out that he also spends Tuesdays and Fridays working at the National Library in Kolkata.

The Sundays that he spends in Kalyani – he tends to his large garden. He took us around his garden – with all sorts of flower plants, fruit trees and the like. It was an extensive set up he had. I asked him where did he get all this energy. He looked at me for some time and asked “What else would you expect one to do?”. That was the best answer ever. I was not sure I had an answer.

We went back inside from his garden for a cup of tea. He regaled me and my brother with stories of undivided India from the early twentieth century. (He was born in Bangladesh but moved to India). He had more stories about freedom fighters from those days than I had ever heard before. My brother and I had an absolutely fantastic time! Both of us agreed to meet him again – either in Kolkata or in Kalyani.

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14 September 2015

A different kind of “back of the envelope” calculation

I had just come out of an afternoon nap (since I come to India for a few days only, I do not even bother to try to get over jet lag – I sleep for three-four hours in afternoon and about the same at night) and stepped into the living room. In India, if you have an air conditioning at home, it is usually in the bedroom only. So, that makes for some good sleep for me. But when you come out of that room, it is like you cut through a whole room of heat and humidity to get to wherever you are trying to get to. For a person like me, who wears glasses, the “wherever you are trying to get to” is often a large approximation since the glasses get fogged up in about a nano-second.

I sat down on the chair, took my glasses out, wiped them with the corner of my shirt, put them back on and this was the sight I was hit with. My brother in law was calling somebody and my mother was rattling off something from what looked like a large brown piece of paper. Upon closer inspection, it actually looked like a large envelope.

My curiosity got the better of me. After she was done, I asked if I could have a look at the paper. It was indeed a large brown envelope. It had nothing inside of it. However, on both sides of the envelope, she had scribbled a lot of phone numbers. I realized that envelope was her contact list.

I followed her to the kitchen and had the obvious question. Why was she using an envelope instead of a notebook? Her answer was that she did not have that many phone numbers anyways and she did not want to waste a whole notebook for that!!! So, I offered to punch in all the numbers in her phone and keep them stored so she would not have to type them in every time. She immediately protested. Apparently that was getting too high tech for her. She wanted to be left alone with the envelope.

Fair enough, I said. But what if she lost the envelope – which she can be prone to. She agreed that she had no answer to that. I asked her to call me if that ever happened. I let her know that I have all those numbers in my contact list. She agreed that it was the best solution. I don’t think she stopped for a moment to wonder why do I have the phone number of the guy who delivers her milk every morning with me. What I really did was simply take pictures of both side of the envelope on my phone and saved it. I will have to send her two printouts when I get that call !!!

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