5 weighings maximum
it is possible with just one weighing

s=same
d=different

worst case scenario is 3rd last or 2nd last ball

s1 s2 s3 s4 s5 s6 s7 d s8

1st s1 and s2
2nd s3 and s4
3rd s5 and s6
4th s7 and d
5th s7 and s8 which then determines it is d or
5th d and s8 but you leave d on same side of scale and it will move same way as before which means it is the different ball.

Sorry Q,
That is not correct.

Hint will come later today if no one has solved the ball question.

Ok I found a way to do it in 4 worst case scenario. Will post if I am correct.

keep trying Q

Here's a hint, and its a biggy. So only peek if you're absolutely sure you don't like challenges:

If you knew that the odd ball that was actually filled with Helium (i.e. you know that it will be lighter than the others), there exists a strategy to always find that ball in only 2 weighings. Find that strategy, and apply it to this problem. :confused: :D

cheers.

My solution for 2 steps if weight of odd-ball is known, i.e. heavier or lighter. In this case I will assume lighter.

Split balls into 3 groups and compare the weight of the first two groups. Outcome will either be 1) equal weight in which case the oddball is in group 3 or 2) the light ball is in one of the two groups measured.

Now compare the weight of two of the balls in the group containing the oddball. if one is lighter than that is the odd ball, if it is equal than the oddball is the ball not weighed.

Now, I am having problems going from that solution to a scenario where weight of the oddball isn't known. But I may have something...

For the actual question with unknown weight of oddball:

Split into 3 groups and compare group 1 and 2. Either they are equal or they are not.

A. If equal than oddball is in group 3 and 2 more weighings are required from balls in group 3 to determine the odd ball - solution in 3 steps

B. If unequal than randomly measure group 1 or 2 vs. group 3. This will tell you which group the odd ball is in and whether it is heavier or lighter. Now, knowing the weight of the ball, a final measurement of two of the balls in the group containing the oddball will tell you which one of the 3 it is. - solution in 3 steps

Hey, not bad. When I started typing the answer I thought I had a 4 weighing solution. But by the end, I had a 3 answer solution. I'll take it and hope that it is right.

Proteosome, you nailed it. Well done. :D

ok I did look at your clue but it didn't help but something popped in my head which was a variation of what I did to get my answer above.

I said 4 by grouping them into groups of 3 and weighing the first two groups and if the weight was the same I would remove them and weigh the final group.

Now if you leave them on you eliminate 1 extra step so you can actually do it in 3.

sss sss sds

weigh sss and sss. Then add s and d. Now you know it was one of the two balls. Remove either ball that you just added and add the remaining ball. If the scale balances then it is the ball you removed. If it does not balance then it is the ball you left on the scale.

Kind of an easy one.......or so it seems.

A bottle of soda costs $3. The soda is worth $2 more than the bottle.
How much is the bottle worth?

Cursory review would put the bottle at:
$.50;
B + S = $3 (bottle of soda, which I assume includes the cost of the bottle)
B + (B+$2) = $3
2B = $1
B= $0.5, and soda= $2.5

But these quizzes are never that easy so I am going to assume there is some word play here??

I've mulled over Nuje's quiz a couple of times and have yet to find a pattern. At first it seems like there is a geometric pattern occuring, but the value 2321 makes it much more complex. I then tried looking for substitution - alphabet, ASCII, Hex, Oct, chronological.

Nothing yet. :(

nope 99gecko it was that easy.

I'm still trying to find a pattern with Nuje as well.

Here's a hint: trying saying each line.
That might help.

Here's the answer
3
1 3
1 1 1 3
3 1 1 3
2 3 2 1
2 2 1 3 1 1
2 2 3 1 1 3
Do we know how/why?

Here's a hint: trying saying each line.
That might help.

Here's the answer
3
1 3
1 1 1 3
3 1 1 3
2 3 2 1
2 2 1 3 1 1
2 2 3 1 1 3
Do we know how/why?
Gee that one's crazy Nuje. I stared for about the last hour and finally saw it. But only because of your hint and looking at the answer. I kinda like questions where you're told the answer and asked to explain.


Quite literally, you're saying, in order, how many of each digit is in the line above it.

First number is 3
Now you say there was "one 3" in the line above...hence 1 3
Now you say there are "one 1 and one 3"...hence 1 1 1 3
Now you say there are "three 1's and one 3"....hence 3 1 1 3
Now you say there are "two 3's and two 1's"....hence 2 3 2 1
Now you say there are "two 2's, one 3 and one 1"....hence 2 2 1 3 1 1
So finally, there are "two 2's, three 1's and one 3".....hence 2 2 3 1 1 3

I got it (used a different starting number so it wouldn't be google-able) from a "Questions found on Google's job application" page somewhere (Google maybe?) a few years ago.
I always thought that it was a great type of question to see how well people are at thinking differently - or looking at problems/questions from different angles.

Maybe the hint should be: say aloud how many of each digit you see on each line.

Four members of the Panduloos tribe were hunting in the deepest part of the Amazon. They need to cross a dangerous rope bridge traversing a deadly gorge to get back to the safety of their village at night.

Unfortunately, they only have one torch which only has enough fuel left for seventeen minutes. The rope bridge is much too dangerous to cross without illumination. Due to the fragile ropes from which it is constructed, and the otherwise poor design, it can only support two people at any given time.

All of the tribe members walk at a different speed. The youngest, "A", can make the crossing in 1 minute. The second fastest is his brother "B" who can do the crossing in 2 minutes. Their father "C" requires 5 minutes, while the wise elder "D" takes 10 minutes to cross.

Anyone who doesn't make it completely across (and soon), will likely be found at dawn; either in the belly of a wild beast, or on a heap of rocks at the bottom of the gorge.

How do the tribesmen make it across to safety before the torch goes out?

(And there is more than one solution :))

How long is this bridge? Can one person with the torch be at one end of the bridge, while the other person hops on at the other end?

Ok, here is my solution:


A+B cross = 2 minutes
A returns = 1 min
C + D cross = 10 min
B returns = 2 min
A+B cross = 2 min
total time = 17 min.

How long is this bridge? Can one person with the torch be at one end of the bridge, while the other person hops on at the other end?
Nope
Ok, here is my solution:

Well, done. Now can you get the second solution? :D

i don't know how to censor my answer.

A+B=2
B return=2
C+D=10
A return=1
A+B=2

a slight variation to the other answer, but i guess its still unique.

well done captain.

btw, spoiler tags are done by surrounding the text you wish to hide like this:

[spoiler]your hidden text goes here[/spoiler ]

just remove the last space after the letter r - I had to leave it for demonstration purposes.