top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

What is the least number of times you need to use seesaw to identify the person who has the different weight?

–1 vote
282 views

There are 12 people and a seesaw on an island, and you have the following information:

  • There is one islander who weighs differently than the other 11, but you don't know which one, nor if they are heavier or lighter.
  • You may use the seesaw to compare the weights of any two sets of islanders of your choosing.
  • Each of the twelve islanders is uniquely identifiable and can be weighed more than once.

What is the least number of times you need to use the seesaw in order to guarantee that you can identify the person who has the different weight?

posted Jan 23, 2017 by anonymous

Looking for solution? Promote on:
Facebook Share Button Twitter Share Button LinkedIn Share Button




Similar Puzzles
0 votes

There are 40 gloves in a drawer: 10 pair of white gloves, 5 pairs of black gloves, 3 pairs of brown, and 2 pairs of gray. You select the gloves in the dark and can check them only after a selection has been made. What is the smallest number of gloves you need to select to guarantee at least one matching pair?

+3 votes

You have 19 eggs.
18 of them have the same weight and 1 of them is different,
but you do not know if it is heavier or lighter than the others.

Using the best possible strategy, in the worst case scenario,
how many weighing do we need to perform
in order to correctly identify the different egg?

Edit : You do not necessarily need to find if the egg is heavier or lighter than the others.

0 votes

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

0 votes

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

...