MIND GAMES
Tin boxes have no emotions
Aditya Rishi

If we don’t outthink it now, the machine will soon be thinking better than the human mind that built it. What it will think of us then is not certain. Tin boxes don’t have emotions, chip or no chip. The computer in your head is still the greatest, the fastest, the most efficient, then why isn’t it more accurate than these tin boxes? You have not much time to think.

My computer had been behaving oddly six weeks ago. Some of you outthought it, and now I know what indeed was on its mind. All the whole numbers (integers) between 2 and 400 had appeared on the screen. For a while, I didn’t know what to do. Then, I entered a number and it got highlighted, while some of the other numbers were erased. I noticed that the computer was running a countdown at the bottom of the screen; I started pressing all the keys, but couldn’t stop the countdown and my computer crashed.

"I went to another computer and saw the same numbers on it. This time, I did some thinking and observed that whenever I entered a trial number, all screen numbers divisible by that number were erased. Soon, this second machine was also gone." Now you sit in front of a computer, enter a trial number and all screen numbers divisible by the trial number (except the trial number itself) are erased. Suddenly, you see a message on your screen: "Leave only prime numbers on the screen in the least number of attempts. The countdown begins.

"The minimum number of attempts would be 8, which is the number of prime numbers between 2 and 20, i.e. 2, 3, 5, 7, 11, 13, 17, 19," says Ankur Gupta, who is in MBBS 4th year in the All-India Institute of Medical Sciences, New Delhi. The others who hold this opinion are Preetinder Singh, Chetan from Ludhiana, Vimal Jit Kaur and Anurag from Bhavan Vidyalaya (Chandigarh), who has even written a program to show how the evil numbers on the computer screen think. According to the program, there are only 78 prime numbers between 2 and 400.

"The solution is to enter all prime numbers starting from the smallest. That means 2, 3, 5, 7, 11, 13 and 17. After entering these numbers, only prime numbers will be left on the screen," says Viney Yadav, who is from IIT, Madras (Chennai), and Parminder Singh Sandhu, who is from Ambala Cantonment and calls this disease numbermania.

Vikas Vashisht, Department of Anthropology, Punjab University, has a different idea: "First 4 prime numbers are well equipped to do the job.

The number 2 deletes half the series by deleting every even number, the number 3 deletes every 6th number, the number 5 deletes all numbers ending in 5 and finally, the number 7 deletes the rest, leaving only prime numbers." Baldeep Singh from Gurdaspur and Shikha Kapila from Patiala will agree with your views, Vikas.

The eight-step solution seems to be the ideal from here, but you can always go back to the numbers and check. Sometimes, we don’t realise how much time we have to work on a problem. You had six weeks and now you have all the time to cross check, but if anyone of you took more than 10 seconds to key in the solution, consider the tin box to have won. Like I said, you have not much time to think. We ought to challenge our brain more often. Olympics, then?

(Write at Mind Games, Saturday Extra, The Tribune, or aditya@tribunemail.com)