Uni Interview Questions!

So I recently had a uni interview for engineering and got asked some (what I thought) interesting questions

1) You have a drawer of 10 blue socks and 10 red socks. Imagine you're in the dark, how many single socks do you have to take out to guarantee you have a matching pair?

2) There are three rooms:
Room A contains raging fires.
Room B contains Lions which haven't eaten for 3 years.
Room C contains murderers waiting for you.
Which room should you enter?

3) You have 6 glasses lined up, 1,2,3,4,5,6.
Glasses 1,2,3 are filled with orange juice. 4,5,6 are empty. By moving only ONE glass, how do you create a situation where the glasses are alternately filled with juice?

I'll post up some others if you like these, answers will follow

Anyone else got any ideas about number 1?

2 into 5 and replace, right the first time

No 1 = 3
No need to get out 11, because with 3 you either get all 3 the same colour, or 2 of one colour and 1 the other.

And similarly, if you wanted 2 pairs, you'd take out 5 socks

Another question:

You have a biased coin (It might favour heads say). How can you use it to make an unbiased decision by flipping it?

The default biased coin answer is to keep flipping until you get an equal number of heads/tails
Eg
1) head. - don't accept it yet
2) tail - that's 50/50 so accept heads

Or
1) head
2) head
3) tail
4) tail
50/50 again so then accept heads

My problem with the default answer is the bias has been heads, when 50/50 occurs the first to meet the equal number will be the biased side
Therefore the biased answer has been obtained in a mathematically unbiased way
But does that mean you select the alternate side - it would still mean you have a bias

What he theory does is to extrapolate and proove that at some point on a 50/50 throw of a coin what appears to be a bias can eventually be made 50/50 if you keep on going an infinite number of times
If it really is biased then heads, heads, heads, heads etc does not help you

For the coin problem, what someone suggested was that:

You flip twice. If you get heads then heads again dismiss it.
If you get tails then tails again, dismiss it. These probabilities are obviously not 0.25 exactly because of the biased coin.

What you should instead do is assign choice A to heads then tails.
Assign choice B to tails then heads. Since the probabilities for either choice A or B are the same, you can make the unbiased decision

Speaking from experience, questions like these never come up on job interviews. Just saying.

These kinds of questions are directed to thought processes and analysing a situation. Very appropriate to a skill such as engiineering, and as in the original post they were questions for a university interview. A situation where the mindset of the individual for suitabiliity of course and as compared to another individual when filling available spaces.

It can also be a matter of how important the questions are in the interview. It may be whether you can get the right or optimum answer, it could also just be a question to gauge the interviewees response or to get any answer and then see if they can elaborate on why that is their answer.

I am an interviewer and they are not the sort of questions I ask, but that is because I have a corporate policy and criteria on interviews. I am after an example from the interviewee of a situation to demonstrate their 'competence' in an area of skills - then see if I can work out they are giving me textbook answers or they can elaborate on what they did, what they would do better etc.
In addition to the generic skills/competences I also want to see who will be best suited to the specific job, I can get some clues from someones experience, but that only tells me if they have done something similar and leaves out the potential someone may have - especially someone looking for their first job.

That puts me in the situation of trying to get something extra out of the interview, part of that is the general conversation around the questions. I could not ask questions like the examples above, but I can work things around to pick people appropriate for the job.

different unis bring up all sorts of weird questions. wait until you go for placements and they do phone interviews. My house mate has had a few and he was obsessing about how to answer the phone.

1) You need to take three to be guaranteed a pair. That way you will either get a red pair, a blue pair or one of each from the first two picks, so you'll either have a pair already or be in a position where one sock of either colour would give you a pair on the third pick.

2) Room B because after 3 years without food there wouldn't be any lions left alive.

3) You pick up glass 2 and pour the contents into glass 5.

I actually got asked question 1 & 3 one my University interview for Engineering last year!