There are 10 pails. 9 of them contain non-poisonous pills while only 1 contains poisonous pills.All of the pails and pills are of the same colour.How to differentiate the one with the poisonous pills.Non-poisonous pills each weighs 10 gram while poisonous pills each weighs 9 gram.You can only use the weighing scale provided once.

Take a pill from each pail, keeping them in order. One by one, put a pill on the scale, when the amount goes up by 9 instead of 10, that one is the poisonous pill...

Sounded good in my head anyway...

I answered that but my friend says only can use the reading of the weighing scale once

But you are using it once... just taking a really long time... HA!

You can have a skittles party and hope you win.