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# An Interesting Puzzle

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Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
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08 Jan 2012, 22:45
2
Yesterday's newspaper had this puzzle and knowing I like Math, my hubby challenged me to solve it. I must confess, I was a little stumped when it heard it first but I knew there had to be a logical solution so I started thinking and then of course - very simple yet smart!

Now, without wasting more of your time, let me give you the puzzle:

Using only five 0s (no other digits, just 0, 0, 0, 0 and 0) and any mathematical operators, make 120.

Please put your solution under the spoiler tag so that people don't stumble on it before they get a chance to think on their own.

If you need a hint, let me know!
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Karishma
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09 Jan 2012, 06:56
2
That's my take:

(0!+0!+0!+0!+0!)!

or

(x^0+x^0+x^0+x^0+x^0)! where x is a non-zero number.

Very interesting! Thanks for posting!
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09 Jan 2012, 06:59
1
0! = 1..

(0!+0!+0!+0!+0!)! = 5! = 120

Good question

Kudos to walker for beating me to it
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09 Jan 2012, 11:17
1
(0!+0!+0!+0!+!0)!
Intern
Joined: 31 Jul 2011
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09 Jan 2012, 19:59
1
(0! + 0! + 0! + 0! + 0!)!
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
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Location: Pune, India

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09 Jan 2012, 21:06
It is great to see that many people were able to arrive at the answer. Great job! Let's still stick to spoiler tags in case some other people want to try it.
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Karishma
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10 Jan 2012, 06:55
nice question. since it's already been answered a handful of times, no need to repeat it here.
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10 Jan 2012, 22:56
(0!+0!+0!+0!+0!)! =120
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kudos me if you like my post.

Attitude determine everything.
all the best and God bless you.
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12 Jan 2012, 02:50
nice q...used the same technique as others
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13 Jan 2012, 05:09
Even though such a question will never appear on GMAT, there is a great learning here - when you think something is impossible, you just have to cool off , relax your mind and start thinking afresh.
The moment I heard 'using only 0s', my first instinct was 'what!? You can add/subtract/multiply/divide whatever, you will never get any other number'. So then I thought that since there has to be a solution, I am missing something so I should back up and review what I know. Then, all I wanted to do was to figure out an operator which I could use with 0 to give me another number. That's when 0! came to mind and as you can see, after that all you need is 5 secs to fit it in 120. I do hope your takeaway from this question is this:

When you read a Problem Solving question and think that it cannot be solved, all you need to do is keep your cool and think about the first thing you need to figure out. Other steps will follow automatically. You know that it can be done so you can do it too.

(Disclaimer: I do not advice you to waste too much time on any one question during the actual exam. In the actual exam, sometimes, you might need to say, "I know we can solve it but I don't think I can in the given time frame so I should instead move on to the next question." You can take your time during practice at home.)
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09 Feb 2019, 21:41
I did it with another approach

Antilog(0!) * Antilog (0!) + ( Antilog(0!) * (0! +0!))

Is it acceptable?

Posted from my mobile device
Re: An Interesting Puzzle   [#permalink] 09 Feb 2019, 21:41
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