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silly math question

Problem Solving — algebra and arithmetic (GMAT Focus Edition)
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silly math question

by Gurpinder » Mon Jun 13, 2011 11:37 am
hi guys,

66 / (-33) x |-9|

= [spoiler]-18....how?[/spoiler]

I keep getting -2/9
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by sunilramu » Mon Jun 13, 2011 12:57 pm
66 / (-33) x |-9|
=> -2 x |-9|
=> -2 x 9
=> -18
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by champ0007 » Mon Jun 13, 2011 12:59 pm
|-9| is in the numerator ...

66/((-33) x |-9|) ---> -2/9 which is what you are getting...

66\(-33) x |-9| = (66 x |-9|) / (-33) = -18

Just check it out
Last edited by champ0007 on Mon Jun 13, 2011 1:01 pm, edited 1 time in total.
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by Gurpinder » Mon Jun 13, 2011 1:00 pm
66/(-33 x |-9| )

2 / (-1) x 9

-2/9

--> what am i doing wrong?


k let me make sure....
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by MBA.Aspirant » Mon Jun 13, 2011 1:44 pm
Gurpinder wrote:hi guys,

66 / (-33) x |-9|

= [spoiler]-18....how?[/spoiler]

I keep getting -2/9
66/-33 * |-9|

-2 * 9 = -18
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by phoenix111 » Thu Jun 16, 2011 8:58 am
Edited
Last edited by phoenix111 on Sat Oct 08, 2011 12:37 am, edited 1 time in total.
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by Gurpinder » Fri Jun 17, 2011 6:03 am
Thx for all ur replies.

I was making this mistake: 66/(-33 x |-9| )

It's actually: 66/-33 x |-9| which = 18
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by kaushikkumar1987 » Sat Jun 18, 2011 2:17 pm
BODMAS is fine but have you thought about PEMDAS? Not different but I kind of feel more comfortable with PEMDAS (Parenthesis, Exponent, Multiplication-Division, Addition-Subtraction).

Also, Please Excuse My Dear Aunt Sally (PEMDAS) :)

Good luck,
Kaushik K
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by Tani » Sun Jun 19, 2011 1:04 pm
When using PEMDAS it is important to remember MD and AS are done left to right, not multiplication first and then division and not addition and then subtraction.

For example

8-3+7 is 12, not -2.
Tani Wolff
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by Kemmy G » Wed Jun 22, 2011 10:59 am
Hello Gurpinder.
Let me see if I can clear this up for you.

Now the equation says-
66 / (-33) x |-9|

Let me start with 66/(-33). I'm sure you know the term PEMDAS. It gives us the order in which to solve math operations. So just to refresh, it's P(arenthesis), E(xponents), M(ultiplication), D(ivision), A(ddition), and S(ubtraction). So, using PEMDAS, we solve the problem with a parenthesis first i.e. 66/(-33). -33 in 66= -2.

The equation is now -2 x |-9|. This brings us to the second operation. The symbol || usually stands for absolute value. Absolute value simply means how far away a number is away from zero. So any number in those two lines always comes out positive whether it was originally negative or positive. The absolute value of -9 and 9 is 9: they're nine numbers away from zero on either side. That's why absolute value problems usually have 2 solutions- it cld be negative or positive.

So, when we remove the absolute value symbol, |-9| becomes 9.

Therefore, -2 x 9= -18. (Don't forget that 2 is negative!)
Hope this helps, :-)
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