It is currently 23 Nov 2017, 13:53

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Stupid Algerbra Questions

Author Message
TAGS:

### Hide Tags

Manager
Joined: 24 May 2010
Posts: 79

Kudos [?]: 61 [0], given: 1

### Show Tags

10 Aug 2010, 12:37
I have to solve this for Y. Here are the steps that I took where did I go wrong.

$$100-y=\frac{100,000}{(100+x)}$$
Subtract 100 from both sides
$$-y=\frac{100,000}{(100+x)}-100$$

multiply both sides by -1
$$y=\frac{-100,000}{(100+x)}+100$$

The anser given is
$$y=100-\frac{100,000}{(100+x)}$$

Are these the same things if this were so then

7-6
would eauly
-7+6 which it does not

Where am I going wrong

Last edited by bb on 10 Aug 2010, 13:21, edited 2 times in total.
formulas

Kudos [?]: 61 [0], given: 1

Manager
Joined: 29 Jul 2010
Posts: 124

Kudos [?]: 3 [0], given: 47

### Show Tags

10 Aug 2010, 13:03
Where are our mathematicians )

Kudos [?]: 3 [0], given: 47

Founder
Joined: 04 Dec 2002
Posts: 15883

Kudos [?]: 29115 [0], given: 5272

Location: United States (WA)
GMAT 1: 750 Q49 V42

### Show Tags

10 Aug 2010, 13:21
I have put it into a readable format with formulas.
What is the source of this question?
_________________

Founder of GMAT Club

Just starting out with GMAT? Start here... or use our Daily Study Plan

Co-author of the GMAT Club tests

Kudos [?]: 29115 [0], given: 5272

Intern
Joined: 03 Aug 2010
Posts: 26

Kudos [?]: 11 [0], given: 0

Schools: Sloan '14 (M)
GRE 1: 337 Q168 V169
WE: Engineering (Energy and Utilities)

### Show Tags

10 Aug 2010, 13:40
The two expressions for y are equivalent due to the commutative property of addition (a + b = b + a and in this case a = 100 and b = the fraction including the negative sign). The two expressions involving 7 and 6 are not analogous to the two expressions involving 100 and the fraction.

Kudos [?]: 11 [0], given: 0

Senior Manager
Status: Time to step up the tempo
Joined: 24 Jun 2010
Posts: 404

Kudos [?]: 259 [0], given: 50

Location: Milky way
Schools: ISB, Tepper - CMU, Chicago Booth, LSB

### Show Tags

10 Aug 2010, 17:38
Quote:
multiply both sides by -1
y=$$\frac{-100,000}{(100+x)}+100$$

The anser given is
y=100-$$\frac{100,000}{(100+x)}$$

Are these the same things if this were so then

7-6
would eauly
-7+6 which it does not

Where am I going wrong

y in the both of the above scenario is the same if we keep x as a variable. 7-6 is not same as -7+6 since we know the exact value of each of the numbers.

The value of y in the above scenario depends on the value of x. If x is zero then y would be negative, if x >= 999900 then y is positive.

Hope I have not confused you further
_________________

Support GMAT Club by putting a GMAT Club badge on your blog

Kudos [?]: 259 [0], given: 50

Manager
Joined: 25 Jun 2010
Posts: 91

Kudos [?]: 46 [0], given: 0

### Show Tags

10 Aug 2010, 18:46
7-6 = -6+7
this is right. You have just changed the order of the numbers.

Posted from my mobile device

Kudos [?]: 46 [0], given: 0

Re: Stupid Algerbra Questions   [#permalink] 10 Aug 2010, 18:46
Display posts from previous: Sort by