Question

There are 8 pills and they are all the same size and colour.
One pill weigh slightly more and is poisonous.
You have a balanced scale and you can only use it twice.
How can you find the poisonous pill?

Answer 1

Separate 8 pills into 3 groups, 3+3+2 pills
1. First weight 3 x 3 pills, if they are equal then go to step 2.1, if one is heavier then got to step 2.2
2.1 Weight 2 pills- heavier one is poisonous
2.2 Weight 1 x 1 pills from heavier group of 3 pills, if one of 2 is heavier, then this is the poisonous one. If they are equal, then the remaining one from the group is poisonous