You have 15 tiny gold bars and a balance scale. One of the bars is lighter than the others, but you can't tell the difference by feel. What is least number of times you could use the scale to determine which one is the light one?
Pls elaborate
2007-12-19 16:56:11 · 5 answers · asked by Anonymous in Entertainment & Music ➔ Jokes & Riddles
4
oops 3.
You only need 4 if you do not know if the bar is heavier or lighter.
Actually you should word the question as
"What is least number of times you could use the scale to be certain to determine which one is the light one?" as there is a possibility that a probabilistic single weighing could be lucky enough to determine it.
2007-12-19 17:05:45 · answer #1 · answered by J C 5 · 0⤊ 1⤋
2
2007-12-20 01:00:27 · answer #2 · answered by kalai 4 · 0⤊ 1⤋
3
you would put 7 on one side and 7 on the other, if it is equal you would know that its the one you didnt weigh. then you would do 3 and 3 and then 1 and 1.
2007-12-20 01:02:16 · answer #3 · answered by Howdy! 5 · 2⤊ 0⤋
2? because you leave 7 on each side and there's a chance you could be holding the lighter one...
2007-12-20 01:30:13 · answer #4 · answered by just me being me 4 · 0⤊ 1⤋
1 If you pick up the lightest one and one other the first time you will know which is lightest.
2007-12-20 00:59:57 · answer #5 · answered by haair 3 · 0⤊ 2⤋