Name: Anonymous 2009-10-01 16:22
I got asked this question at least in 3 different job interviews! What's the point? What are they "looking" for?
At least the next 2 times, I already had the answer and just spewed it out.
The question:
You have 12 identical balls but one slightly heavier. You also have a balance scale. How would you isolate the slightly heavier ball using the balance scale as little as possible?
Answer:
Divide the balls into 2 groups of 6. Use the balance scale to find the slightly heavier group and discard the lighter one. Then divide the remaining 6 into 2 groups of 3 and weight on the scale. Discard the lighter 3 balls. Now take 2 of the remaining 3 balls and compare them on the scale. If they weight the same, then the left over one is heavier. If there's a difference, then take the heavier one on the scale.
At least the next 2 times, I already had the answer and just spewed it out.
The question:
You have 12 identical balls but one slightly heavier. You also have a balance scale. How would you isolate the slightly heavier ball using the balance scale as little as possible?
Answer:
Divide the balls into 2 groups of 6. Use the balance scale to find the slightly heavier group and discard the lighter one. Then divide the remaining 6 into 2 groups of 3 and weight on the scale. Discard the lighter 3 balls. Now take 2 of the remaining 3 balls and compare them on the scale. If they weight the same, then the left over one is heavier. If there's a difference, then take the heavier one on the scale.