You have a balanced scale. How can you find the lighter ball in at MOST two weighings? The answer is an equation that solves for the lightest ball!
2006-09-07 16:42:19 · 5 answers · asked by ach_austin 1 in Science & Mathematics ➔ Mathematics
how come this question comes up every 2 days?
number the balls 1 to 8
weight 1,2,3 vs 4,5,6
case 1: balance, i.e either 7 or 8 is lighter
weight 7 vs 8
case 2: found 1,2 or 3 is lighter
weight 1 vs 2, if balance, 3 is lighter.
etc. etc.
2006-09-07 16:49:52 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Divide the balls into 3 groups:
\
a. 3 balls
b. 3 balls
c. 2 ball
First weighing:
weigh Group A against Group B.
There are three possible results.
1. Group A is lighter than group B:
Conclusion: A contains the lighter ball.
2. Group B is lighter than group A:
Conclusion: B contains the lighter ball.
3. Group A and Group B balance:
Conclusion: Group C contains the lighter ball.
Second Weighing:
Take two balls from the group containing the lighter ball. Weigh then against each other.
If group C had the lighter ball, the second weighing will show which one it is.
If group A or B had the lighter ball, you will be weighing 2 of the 3 balls against each other. If one of the two balls is lighter than the other one being weighed, it is the lighter ball. If the two balls being weighed balance, the other not weighed is the lighter ball.
2006-09-07 16:54:22 · answer #2 · answered by o41655 4 · 0⤊ 0⤋
1- Divide them to three groups: 3, 3, and 2 balls.
2- Put those groups which have 3 balls in both sides of the balanced scale.
a- If they weigh the same, then the lighter ball is in the other group (2 balls). It would be easy to put them in the balance scale to see which one is the lighter.
b- If one of these groups is lighter, it means the lighter ball is in that group. So, you put 2 balls of that group in the balance scale. If they weigh the same, the other one, the third ball, is the lighter one. Otherwise, you can see that one of them is lighter and you have found the answer
2006-09-07 17:20:06 · answer #3 · answered by Arash 3 · 0⤊ 0⤋
what the hell are you talking about both my balls weigh the same. where are you guys getting 8 balls? are there 4 gay men? whats the story?
2006-09-08 22:10:08 · answer #4 · answered by Yahoo Blows 1 · 0⤊ 0⤋
i have a headache
2006-09-07 16:48:24 · answer #5 · answered by Anonymous · 0⤊ 0⤋