(June 17, 2017 at 4:48 pm)Jesster Wrote:(June 17, 2017 at 4:21 pm)Alex K Wrote: You have eight identical-looking marbles, seven are are the same weight, one is slightly heavier.
You are given a balance which you may use exactly twice. How do you identify the slightly heavier marble with 100% certainty?
Put 6 marbles in the scale, 3 on each side.
If the original measure is balanced, weigh remaining 2 to see which is heavier and you have your answer.
If the original measure is not balanced, weigh 2 of the 3 marbles from the heavier side.
If those are balanced, the heavy marble was the one left out.
If they are unbalanced, you've found it on the heavier side.
All I can say is