24 Points

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Saturday, May 23. 2009

24 Points

Somedays back, one of my co-workers popped this mathematical question for us to think about. It is fairly simple but complex for our minds. Anyway, here’s the question:-

5 . 5 . 5 . 5 . 5 = 24
Replace the . with any of the following operators: +, -, *, /. You may add brackets anywhere in-between the numbers or operators.

There are many solutions, have fun!
Posted by iphoting in Thoughts, Work at 16:01 | Comments (12) | Trackbacks (0) | Top Exits (0)
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(5+5+5)/5 +5 = 2(4)

Can?
#1 ~autolycus (Homepage) on 2009-05-25 10:55 (Reply)
Hehe, I think it’ll be acceptable thanks to its creativity. =)
#1.1 iphoting on 2009-05-30 10:58 (Reply)
Are powers allowed? I can’t think of a solution that doesn’t involve 5^5. =\
#2 Demel (Homepage) on 2009-05-25 18:40 (Reply)
Sure, feel free to use exponents, but remember the requirement to use five 5s only.
#2.1 iphoting on 2009-05-30 10:59 (Reply)
[5 - (5/5)] x 5 + 5
#3 winston on 2009-05-30 21:30 (Reply)
Hmm... piping your input into Mathematica reveals the answer as 25. The solution needs to produce 24 for it to be valid.

Nice attempt though. =)
#3.1 iphoting on 2009-05-30 21:34 (Reply)
I think it’s more challenging to use / * - + and ( ) only... :-)

Otherwise you can do things like...

5*5 - 5^(5-5) = 24
#4 ~autolycus (Homepage) on 2009-06-01 11:15 (Reply)
That was the precise thing I had in mind, actually. I’ve yet to find any solutions with only the 4 basic operators.

More trying, though.
#5 Demel on 2009-06-02 18:37 (Reply)
how about
(5! + 5*5)/5 - 5 = 24

haha i’ve yet to find a solution with only +-*/ though :-P
#6 qz on 2009-06-13 01:59 (Reply)
That’s quite interesting. I’ve never thought that a factorial could be used. :-P
#6.1 iphoting on 2009-06-13 10:08 (Reply)
Haha, I think I’m the only one who actually met the original terms and conditions. After all, you did say I could put brackets anywhere between the numbers or operators... :-D
#7 ~autolycus (Homepage) on 2009-06-26 20:03 (Reply)
Oh come on, surely this can’t be the most elegant and mathematically acceptable answer, right?

(5 x 5 x 5 - 5) / 5 = 24

:-)
#7.1 iphoting on 2009-06-26 22:07 (Reply)

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