Mind Teasers

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Part 1: This band are having a concert in 17 mins, and they all must cross a bridge to get there. All four members begin on the same side of the bridge. You must help them across. It is night. There is one flash light. A maximum of 2 ppl can cross at once (Don't ask why). Any party who crosses, either 1or 2 ppl, must have the flashlight wiht them. The flashlight must be walked back and forth, etc. Each band member walks at a different speed. A pair must walk at the slower man's pace:

Fred: 1 minute to cross
Bob: 2 mins
Alf: 5 mins
Nick: 10 mins

If you go over 17mins - YOU FAIL.

This is not a trick question and can be done by moving people in the appropriate order. There a two known answers.

Apparently this is part of the test Microsoft give to propective employees. They expect them to do it in 5 mins .

Good Luck.

 

Second answer (a bit similar to first):

Bob and Fred cross (2 min)
Bob goes back (4 min)
Alf and Nick cross (14 min)
Fred goes back (15 min)
Bob and Fred cross (17 min)

Tada! With this "tada" i feel like 2 year old kid.


[This message has been edited by Extremist (edited April 25, 2001).]

 

Try this one!
I am a 4-digit number with no two digits the same. My ones digit is twice my thousands digit and one less than my tens digit. My hundreds digit is the difference between my tens digit and my thousands digit. My thousands digit is an odd number less than 6.
What number am I?

 

Here goes:

1
11
21
1211
111221
312211
13112221
?

If anyone can make the next line, they can consider themselves quite special. I haven't met anyone who solved this yet.

P.s. This of the book "Day of the Ants", so I won't take credit for it.

 

Let's see Gormenghast:
lets use some simple algebra and say the digits are A,B,C & D for the thousand,hundred,ten, & one.
four equations result:
D=2A
D=C-1
B=C-A
A=5,3,or 1

5 can't be correct because that would make D=10 and 1 can't be correct because then D=B=2 so it must be 3, so:
A=3, D=6, C=7 & B=4

voila! the number is 3476

 

I so TOTALLY HATE you people!!

*grumbles something about smarta** engineers and breeding restrictions*

 

This is a quiz written by Einstein last century. Hes aid that 98% of the people in the world cannot solve it.

Facts:
1) There are 5 houses in 5 different colours
2) In each house lives a person with a different nationality
3) These 5 owners drink a certain beverage, smoke a certain type of cigar and keep a certain pet
4) No owner has the same pet, smoke the same brand of cigar or drink the smae drink

Hints :

1: The British lives in a red house
2: The Swede keeps dogs as pets
3: The Dane drinks tea
4: The green house is on the left of the white house (It also means that they are next door)
5: The green house owner drinks coffee
6: The person who smokes Pall Mall rears birds
7: The owner of the yellow house smokes Dunhill
8: The man living in the house right in the center drinks milk
9: The Norwegian lives in the first house
10: The man who smokes Blend lives next to the one who keeps cats
11: The man who keeps horses lives next door to the man who smokes Dunhill
12: The owner who smokes Blue Master drinks beer
13: The German smokes Prince
14: The Norwegian lives next door to the blue house
15: The man who smokes Blend has a neighbour who drinks water.

Question : Who keeps fish (Trout )

 

Grovflab, the answer is:
1113213211.

It's easy, just speak every number and you'll detect what those mean.

 

Grovflab:

1113213211

and then the next two lines would be...

31131211131221
13211311123113112211

do I have it?

Edit:Bah! somebody beat me!

[This message has been edited by Bowie (edited April 25, 2001).]

 

Congrats, the numbers seem to be right. Did you know the solution, or did you actually solve it? I'm not considering you cheaters, but as said, you are the first to solve it.

And yes, it is easy, when you know how to solve it.

 

Good work BTA - the clock doesn't lie!
Unless of course you almighty moderators can stop time or something!

I suppose the purpose of a question such as this would be to test a person's thought process. To initially look at the puzzle one would think that the fastest person should be involved in every trip across the bridge. Of course this isn't the case. The trick to many brain teasers is to avoid the obvious and explore different options. Heh, answering such a question while being under the pressure of an interview panel would be interesting indeed!
Now in the case of a perspective Microsoft Employee this could be very useful; 'Let's see. How many different ways can I make this piece of software crash in the least amount of time?'

No offense to any Microsoft employees out there.

 

Wildfire, I have a book full of similar logic puzzles that I play with while I'm lying in the sun during the summer. It can be solved easily, I'm sure, by process of elimination, but I am SO too lazy to draw up a chart to figure it out...

 

To be honest, I hadn't seen that one before but one similar:

1
11
21
1112
3112
211213
312213
?

 

Bowie, that goes 212223?

Same principle.

 

Simple mathematical principles for this one. But when our maths' teacher asked us a couple of years ago only I found it.Am I modest or what?

Fact: a=b

a=b =>
a*a=b*b => ( I can't write 'a squared' so it
has to be symbolized like this
here. * is times)
a*a=a*b =>
a*a - b*b=a*b - b*b =>
(a-b)(a+b)=b(a-b)
a+b=b =>
2b=b =>
2=1 ?

What was the mistake made here?

 

Smart BTA, I knew I had seen it before, just couldn't remeber it.

 

Yup - You are correct BTA (AFAIK)

You get 2 gold stars