Brain Teaser!

Menlaan · Post by **Menlaan** » Wed Feb 15, 2006 2:09 pm

Take the numbers '2' '4' '6' and '8'' and combine them using any arithmetic operations in any order (but using each number only once) to equal 25.

What's the solution?

I was asked this in an interview today and got stumped. Help NT!

Menlaan

The Kizzy · Post by **The Kizzy** » Wed Feb 15, 2006 2:12 pm

I dont think its possible. All the numbers are even, and you are asked to come up with an odd solution.

Menlaan · Post by **Menlaan** » Wed Feb 15, 2006 2:15 pm

You can make odds by, for example taking 6 divided by 2. However, my interviewer indicated that that specific idea wasn't going to get me there. He also indicated that children have an easier time with this b/c you have to 'think outside the box."

Menlaan

Harrison · Post by **Harrison** » Wed Feb 15, 2006 2:15 pm

Not enough restrictions, can you use the numbers more than once? Can you square/cube them? etc.

Zanchief · Post by **Zanchief** » Wed Feb 15, 2006 2:17 pm

Harrison wrote:Not enough restrictions, can you use the numbers more than once? Can you square/cube them? etc.

I was thinking of that before the children comment~

Menlaan · Post by **Menlaan** » Wed Feb 15, 2006 2:18 pm

You can use them only once, and you can use any arithmetic operations. The way I interpret that is that you can do 4^2 (or 4 squared), but that will use up '4' and '2'. You can also add, subtract, divide, etc.

Menlaan

Eldred · Post by **Eldred** » Wed Feb 15, 2006 2:34 pm

2+8= 10
1+0= 1
4*6= 24
1+24= 25

Zanchief · Post by **Zanchief** » Wed Feb 15, 2006 2:37 pm

Eldred wrote:2+8= 10
1+0= 1
4*6= 24
1+24= 25

lame

Harrison · Post by **Harrison** » Wed Feb 15, 2006 2:37 pm

1 isn't one of the numbers given, neither is 0.

Harrison · Post by **Harrison** » Wed Feb 15, 2006 2:39 pm

And if you're able to use the subsequent numbers in the integers resulting from an operation, that wasn't stated either.

I.E.

(2+8=10) you didn't say we could take the resulting 1 and 0 that creates (10) and use them as such.

Zanchief · Post by **Zanchief** » Wed Feb 15, 2006 2:39 pm

10 = 1 and 0

Harrison · Post by **Harrison** » Wed Feb 15, 2006 2:40 pm

See above

I don't know of any mathematical logic behind taking the 1 and 0 that makes (10) and use them seperately on their own.

Eldred · Post by **Eldred** » Wed Feb 15, 2006 2:43 pm

It's thinking outside the box. Most of the time these types of questions are posed to see ones thought prosses, not just to see if they can do math in their head.

Yamori · Post by **Yamori** » Wed Feb 15, 2006 2:53 pm

6^4 (1296)

Square of 1296= 36

36-8 = 28

28-2 = 26

DAMN

Menlaan · Post by **Menlaan** » Wed Feb 15, 2006 2:54 pm

I think Eldred got it. Thanks!

Yamori, that was close!

Menlaan

Harrison · Post by **Harrison** » Wed Feb 15, 2006 2:55 pm

Yamori wrote:28-2 = 25

Yamori · Post by **Yamori** » Wed Feb 15, 2006 2:57 pm

Harrison wrote:
Yamori wrote:28-2 = 25

yeah im cracked this morning, roffle

Pretty silly that I did the exponents and squares right but did kindergarten subtraction wrong. ><

I blame... the sea.

Tacks · Post by **Tacks** » Wed Feb 15, 2006 2:58 pm

Well I'm more of a math thinker and this was the closest I could come

8 X square root of 6 + square root of 2 + 4 = 25.0101

Yamori · Post by **Yamori** » Wed Feb 15, 2006 3:08 pm

Actually, I dunno if exponents technically work for this - it does use multiples of the same number.

Eldred · Post by **Eldred** » Wed Feb 15, 2006 3:10 pm

The problem is 25 is a rational number and the Square root of 2 and 6 are irrational numbers. Therefor 25.01013105463851983437996072421 non terminating none repeating number. And Rational Numbers can't be Irrational Numbers.

Tacks · Post by **Tacks** » Wed Feb 15, 2006 3:10 pm

Well I don't know how technical it needs to be. In my field of work 25.01 = 25.

I don't expect this to be what they're looking for at all, this is just what I could come up with :P

Eldred · Post by **Eldred** » Wed Feb 15, 2006 3:14 pm

Zanchief Returns wrote:
Eldred wrote:2+8= 10
1+0= 1
4*6= 24
1+24= 25

lame

Lets see you post something then cock goblin.

Tacks · Post by **Tacks** » Wed Feb 15, 2006 3:35 pm

Also technically you never said you can't use OTHER number, you just said you can only use 2,4,6 and 8 once. So according to your question you could do:

8 x 6 divided by 4 + 2 +11=25

or any other combination really

Diekan · Post by **Diekan** » Wed Feb 15, 2006 3:40 pm

Tacks wrote:Well I don't know how technical it needs to be. In my field of work 25.01 = 25.

I don't expect this to be what they're looking for at all, this is just what I could come up with :P

Since when did cash registers stop calculating coin change?

Tacks · Post by **Tacks** » Wed Feb 15, 2006 3:51 pm

ya perhaps i should have been a complete and utter mindless meathead with no skills at all and went into the military instead of living on the streets. nah, i chose college and getting high pay for minimal amounts of work.

PS: thanks for displaying your lack of intelligence by your only post here and thus proving my point~