[wolfgang]

If you have six beakers ,Five of them containing a deadly Toxin in equal amounts, and one beaker contains the Anti-Toxin.

You have a special detector in the form of yellow beads,and you have only three tiny beads(each bead can be used only once).

If you put a bead inside a beaker containing (Toxin) will convert the color of the bead to Blue.

while (Anti-Toxin)will convert its color to Red.

A mixture of equal amounts of both (Toxin) and(Anti-Toxin),will NOT change its color(will remain yellow).

You are allowed to test your mixing results three times only.

you have plenty of empty beakers to be used in mixing,and pipettes to take equal amounts.

If the amount of Toxin in any mixture is more then the Anti-Toxin, the bead will be blue.

If the Anti-Toxin is more than the Toxin,the bead will be red.

How can you know which beaker contains the Anti-Toxin?

Note:broken bead can not detect anything!

Edited April 18, 2011 by wolfgang

[k-man]

1) Mix equal amounts from 1 and 2 and test the mix. If the bead is yellow, test 1 or 2 to find the Anti-Toxin. Done in 2 tests.

2) If the above step produces blue repeat the same for 3 and 4. If the color is yellow, use the third bead to test 3 or 4. Done.

3) If the above step is still blue then use the third bead to test #5. If blue, then the Anti-Toxin is in #6.