Interesting problem

You have 10 rocks in a bag, numbered 1-10 and all have different weights. At the beginning you don't know a thing about their weights, besides that they have different weight. At every step you randomly select two different rocks from the bag and put them on the balance scale, and you can see which one is heavier. What is expected number of steps to find out which rock is the heaviest in the bag?

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Comments (4)

Jan 4, 2014 - 4:49am

Answer should be actually higher than 45, because you definitely need to draw a pair (heaviest rock, second heaviest rock), and expected value of steps for that is 45, and there are also some pairs that you have to draw as well, so your expected value should be higher :)

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