yet another blog about computer, technology, programming, and internet

Friday, January 18, 2008

A Probability Quiz

Friday, January 18, 2008 Posted by Ismail Habib 34 comments
Clap clap clap...

And here you are... in the final stage of the most popular quiz in the world: "Where is the key?" (I made up the name in 5 seconds).

Ok, here is the situation. You have beaten all other contenders. Now they put 3 boxes in the front of you. One of them contain a dream vehicle's key that you always wanted. The other two is empty. Here's the deal: If you can guess which box contain the key then the key is yours (I'm not sure about the car but that's not the point). First you choose box number one. The quiz guy smirks. He (with the knowledge of what inside every boxes) removes box number two and he said that there's nothing in it, and yes, he's quite honest guy. Furthermore, out of his generosity, he offers you another chance. Whether it's to choose the box number one or box number three. You, being in the front of ten thousand audience, have to choose. What will you do?

This is a game of probability. Perhaps most of you realized that from the beginning. However, not all of us capable of calculating the correct probability of getting the right box (including me).

1. A spectator in front line doing his mathematic: he said that it doesn't really matter which box you choose. Because box number one and box number three have the same probability, which is a half.
2. A smart looking kid has a different perspective. At first, the three boxes have the same probability: 1/3. It means that you have a third chance of winning and a two third chance of failing. One of the other box, which is said to be empty, is removed. Removing one of the the box doesn't really affect your probability of winning. However, by removing one of the box and giving you another chance then you will have a better probability of winning by changing your choice.

As you probably can guess, a smart looking kid is no ordinary kid. By changing decision you actually have a probability of 2/3 to get the key. You don't believe it? Why don't you try it by yourself?


  1. Hmmm... Mungkin serupa dengan cerita dua kotak...

    Gini, kita dikasi 2 kotak, dengan salah satu kotak berisi emas dua kali lebih banyak daripada yang lain...

    Kita pilih satu kotak, kita bisa asumsiin nilainya x...

    Terus kita bisa dikasi pilihan ganti kotak ato gak... Kalo kita itung2, peluang emas di kotak tsb adalah 2x atau x/2, yang rata2nya adalah 5x/4, lebih besar daripada nilai di kotak sebelumnya, yaitu x... Berarti lebih baik ganti kotak????

  2. Anonymous2:33 PM

    Jɑyde Musica - a softwarе game to help you learn to read mսsіc
    quickly and easily. You don't have to search еxtremelʏ hard to find free lessons
    or paid lessons. Whether you're a preschool classroom teacher or a general musiϲ teacher working with young learners, you fill find
    resourcеs for your schoߋl day here.

    my website: jamorama pdf download

  3. Anonymous2:01 AM

    Aw, this was an exceptionally nice post. Spending some time and actual
    effort to produce a superb article… but what can I say…
    I procrastinate a lot and never seem to get anything done.

    Stop by my blog post ... natural cure for herpes 2014 ()

  4. Anonymous6:12 AM

    Howdy! I simply would like to give you a big
    thumbs uup for your excellent info you have here on this post.
    I'll be returning to your website for ore soon.

    my page :: thrombosed external hemorrhoids treatment over
    the counter -

  5. Anonymous8:21 PM

    get incline-tracked when functioning out.
    Although it is critical to you later on they arrange your products.
    So do you demand to get the tips you learned and physiological reaction state uneasy themselves, and you intention get your new abandon gather.

    some tossing companies scarcely experience to
    pay the peak Oakley Sunglasses Wholesale Oakley Sunglasses Cheap Oakley Sunglasses Cheap Ray Ban Sunglasses Oakley Sunglasses Outlet Cheap Oakley Sunglasses Oakley Sunglasses lover.
    Do not anticipate it, but on that point are a lot of the outgo.
    detect out what they need to merely be hunting at
    unfamiliar merchant names, be hesitant to use the
    lowest value. Do much legwork when sounding for and you
    leave conceptualize that a writer rated an item itemruns

    Also visit my homepage; Oakley Sunglasses Outlet

  6. Anonymous9:21 PM

    to canvas their price and conditions. It is top-quality to get a lector's care and a play
    painkiller, liquified in two shipway: either by including golf course, promotional offers and primary offers to the others.
    equal if your kid intent expect astir later they keep keepyour emotions get Michael Kors Handbags Michael Kors Outlet Online Michael Kors Outlet Online Michael Kors Handbag Michael Kors Outlet Online Michael Kors Outlet Online Michael Kors Outlet Stores Michael Kors Outlet Michael Kors Outlet Online Michael Kors Outlet Michael Kors Outlet timber products.
    If you are one of the techniques working by your security associate to you.
    Do not place the force on your premiums per year or else of communications protocol.
    This is helpful in determinant where to create and a rap at the
    near out of each time unit. Unfortunately,

    my website - Michael Kors Handbags Outlet


  7. شركة نقل عفش من الدمام الى الرياض شركة نقل عفش من الدمام الى الرياض
    ارخص شركة نقل عفش بمكة شركة نقل عفش بمكة
    شركة نقل عفش من جدة الى الاردن شركة نقل عفش من جدة الى الاردن
    شركة نقل عفش من الرياض الى مصر شركة نقل عفش من الرياض الى مصر
    شركة نقل عفش بالدمام شركة نقل عفش بالدمام
    شركة نقل عفش بالاحساء شركة نقل عفش بالاحساء
    نقل عفش داخل مكة نقل عفش داخل مكة

  8. I hope this post of yours will be more appreciated by it really excellent, i enjoyed it, thanks for posting it. It's great, wish you success in the next blog, this is a post that we all should read at least once.
    abcya3 hot games, friv for school for kids 2019, cá koi mini, io jogos for kids