Riddles, brain puzzles and mathematical problems

[BAndrew]

Why is that so? My method involves neither waiting nor knowledge of prior results. Just do all the steps at the same time. It is the pattern of deaths after 20 hours that will show where the poison is located. I was worried that this wasn't clear with how I worded it in some parts, but it was indeed the intention.

In that case your answer is correct. I misread your answer. There has been a misconception as to whether you need or not to know the outcome of the previous rat before going to the next. Thanks to clearing this. Your answer is correct.

@Bridge
Actually he didn't meant to do this.
Here's what you do:
You split 1024 into Group A of 512 bottles and Group B of 512 bottles (actually 488 and the rest are imaginary)

You give rat 1 to drink group A

You split group A and B to group A1,A2,B1,B2 each of 256 bottles
Give rat 2 to drink A1 and B1 groups.

Continue to do this for 10 steps.

The pattern of the death of the rats determines where the poison is.
So his answer doesn't need more rats or more time.

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My answer to the riddle is the following (maybe it helps you)
We make an array (Rats/Bottles) like this (where X means that the X rat will drink the Y bottle):



So for instance after 20 hours if all of the 10 rats are dead this means that the bottle 1 has the poison. If only rat 10 is dead then the 1000th bottle has the poison. There are 2^10 = 1024 possible combinations so you have 24 that will not be used.

However Neptune's answer is equally correct.