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June 26th, 2014, 05:57 PM   #1
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Very old riddle

There are 3 birds sitting on a branch of a tree.
If you throw a rock and knock 1 bird down,
how many birds are left on the tree?
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June 26th, 2014, 08:44 PM   #2
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None
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June 26th, 2014, 09:12 PM   #3
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2, since a rock makes no noise to scare away...you need a gunshot
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June 26th, 2014, 09:18 PM   #4
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The answer is none.

The beauty of the riddle is that you can't just simply plug in numbers in real life. Real life has a lot of variables.

If it were 3 apples on a tree, then 2 would be left on the branch.
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June 26th, 2014, 11:03 PM   #5
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Here's another:

3 lights in a room; the 3 switches are outside the room.
How can you determine which light each switch is connected to?
You cannot see inside the room while you're doing this;
plus you can enter the room only once.
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June 26th, 2014, 11:07 PM   #6
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If you know that they are all off to start with, you:
  1. flip one switch;
  2. wait a few minutes;
  3. flip the switch again;
  4. flip another switch;
  5. enter.

It's a bit harder if they aren't all off to start with.
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June 26th, 2014, 11:15 PM   #7
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Correct Archie...you get the Electrician Job
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July 3rd, 2014, 09:00 PM   #8
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Quote:
Originally Posted by long_quach View Post
The answer is none.

The beauty of the riddle is that you can't just simply plug in numbers in real life. Real life has a lot of variables.

If it were 3 apples on a tree, then 2 would be left on the branch.
Except that the other two may get fallen due to the vibration impact.
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July 4th, 2014, 02:25 AM   #9
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Quote:
Originally Posted by long_quach View Post
There are 3 birds sitting on a branch of a tree.
If you throw a rock and knock 1 bird down,
how many birds are left on the tree?
Assuming an isolated, closed system,

$\displaystyle 0 \leq x \leq 3, x \in \mathbb{N}^0$,

where $\displaystyle x$ is the number of birds sitting on the branch in the tree and the function describing the rate of change of number of birds in the tree as a function of time is unknown, but non-zero at the time of the rock being thrown.

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July 14th, 2014, 02:55 AM   #10
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Quote:
Originally Posted by long_quach View Post
There are 3 birds sitting on a branch of a tree.
If you throw a rock and knock 1 bird down,
how many birds are left on the tree?
None
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