## warehouse

##### This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 399
Joined: 15 Apr 2009
Location: india
Thanked: 39 times

### warehouse

by xcusemeplz2009 » Fri Nov 13, 2009 3:31 am
Attachments
warehouse.doc
It does not matter how many times you get knocked down , but how many times you get up

Legendary Member
Posts: 869
Joined: 26 Aug 2009
Location: California
Thanked: 13 times
Followed by:3 members
by heshamelaziry » Fri Nov 13, 2009 9:54 am
I picked numbers for 1 and found no prices ----> insuf

Did the same for 2, but no quantities ------> insuff

combo:

(10 * 10 - 11 * 40 / 100 ) * 100 Suffic
Last edited by heshamelaziry on Fri Nov 13, 2009 10:16 am, edited 1 time in total.

Senior | Next Rank: 100 Posts
Posts: 42
Joined: 15 Aug 2008
Location: India
GMAT Score:660
by aks.anupam » Fri Nov 13, 2009 10:13 am
Condition (1): No information about per sofa cost. So revenue can not be calculated. Hence INSUFFICIENT.

Condition (2): No information about number of sofas sold. So Revenue can not be calculated. Hence INSUFFICIENT.

Combining (1) & (2):

Say x is the number of sofas sold last year.
Then this year, number of sofas sold = 1.1x

Selling price per sofa last year be $y Total revenue for last year = xy Selling price per sofa this year =$(30+y)
Total revenue for this year = 1.1x*(30+y)

Percentage increase in revenue

= [[1.1x*(30+y) - xy] / xy] * 100

= [[33x + 1.1xy - xy]/xy ]*100

= [[33 + 0.1y]/y]*100

Y is not known, Hence INSUFFICIENT.

Legendary Member
Posts: 869
Joined: 26 Aug 2009
Location: California
Thanked: 13 times
Followed by:3 members
by heshamelaziry » Fri Nov 13, 2009 10:20 am
aks.anupam wrote:Condition (1): No information about per sofa cost. So revenue can not be calculated. Hence INSUFFICIENT.

Condition (2): No information about number of sofas sold. So Revenue can not be calculated. Hence INSUFFICIENT.

Combining (1) & (2):

Say x is the number of sofas sold last year.
Then this year, number of sofas sold = 1.1x

Selling price per sofa last year be $y Total revenue for last year = xy Selling price per sofa this year =$(30+y)
Total revenue for this year = 1.1x*(30+y)

Percentage increase in revenue

= [[1.1x*(30+y) - xy] / xy] * 100

= [[33x + 1.1xy - xy]/xy ]*100

= [[33 + 0.1y]/y]*100

Y is not known, Hence INSUFFICIENT.

what is wrong with what i did above ? I assigend these:

year 1) 10 sofas, each for $10 year 2) 11 sofas, each for$40

combo : 10 *10 = revenue 1st year. 11 * 40 = revenue 2nd year. percent change = new revenue - old revenue / old revenue *100

what is wrong ?

Senior | Next Rank: 100 Posts
Posts: 42
Joined: 15 Aug 2008
Location: India
GMAT Score:660
by aks.anupam » Fri Nov 13, 2009 10:38 am
I guess 2 assumptions have been made:

1) You have taken 10 sofas sold for the first year, and
2) You have taken $10 as the cost for first year. If you take different values, the percentage revenue increase would change! For check, try putting$ 20 instead of $10: Percentage increase in first case = (11*40 - 10*10)/100 = 340% Percentage increase in second case = (11*50 - 10*20)/200 = 175% Last edited by aks.anupam on Fri Nov 13, 2009 10:41 am, edited 1 time in total. GMAT Instructor Posts: 1302 Joined: 19 Oct 2009 Location: Toronto Thanked: 539 times Followed by:163 members GMAT Score:800 by Testluv » Fri Nov 13, 2009 10:40 am heshamelaziry wrote:I picked numbers for 1 and found no prices ----> insuf Did the same for 2, but no quantities ------> insuff combo: (10 * 10 - 11 * 40 / 100 ) * 100 Suffic Pick a different set of numbers as well! You have to see if the answer will change if you change the numbers you pick! Because if the answer does change, the answer is E! Kaplan Teacher in Toronto Legendary Member Posts: 869 Joined: 26 Aug 2009 Location: California Thanked: 13 times Followed by:3 members by heshamelaziry » Fri Nov 13, 2009 10:42 am WHY PICKING NUMBERS HERE DOESN'T WORK ? percentage change should be the same under the given conditions. I tried different values and got answer 340% each time Last edited by heshamelaziry on Fri Nov 13, 2009 10:45 am, edited 1 time in total. Senior | Next Rank: 100 Posts Posts: 42 Joined: 15 Aug 2008 Location: India GMAT Score:660 by aks.anupam » Fri Nov 13, 2009 10:42 am Kindly see the example I have given above. GMAT Instructor Posts: 1302 Joined: 19 Oct 2009 Location: Toronto Thanked: 539 times Followed by:163 members GMAT Score:800 ### Re: warehouse by Testluv » Fri Nov 13, 2009 10:47 am xcusemeplz2009 wrote:pls give your reasoning Always think about what kind of info you would need to answer the question before approaching the statements. The question is asking us for the percent increase in (sofa) sales. This is a value (not a yes/no) question, so we need a single value for sufficiency. Either we need a special equation that relates the sales between the years, or else we actually need to know the sale prices and numbers sold in each year. Statement One is immediately insufficient as it does not provide us with info about$.

Statement Two is insufficient because we don't know the selling price of last year.

There is no special equation relating sales, and we don't know the acutal sales for each year, or the number sold. Therefore, the answer is E.

But, if at that point, you're not quite convinced, then:
In combination: they sold 10% more sofas and at a rate that is $30 greater than last year. Don't resort to pure algebra here. Quickly pick two different numbers for last year's sale price (and for number sold), and you will see the answer changes. Because we can get multiple values, the statements, even after combination, are not sufficient to answer the question. Choose E. Last edited by Testluv on Fri Nov 13, 2009 1:54 pm, edited 1 time in total. Kaplan Teacher in Toronto GMAT Instructor Posts: 1302 Joined: 19 Oct 2009 Location: Toronto Thanked: 539 times Followed by:163 members GMAT Score:800 by Testluv » Fri Nov 13, 2009 11:07 am heshamelaziry wrote:WHY PICKING NUMBERS HERE DOESN'T WORK ? percentage change should be the same under the given conditions. I tried different values and got answer 340% each time Picking numbers does work. But you have to do it properly. In DS, you need to pick different kinds of numbers to see if the answer to the question will change. We have no info about actual price. We know the price of sofas went up by$30. If this was from $20 to$50, we will have a BIG percent increase. But if the price of the sofas went from $500 to$530, our percent increase will be tiny.
Kaplan Teacher in Toronto

Master | Next Rank: 500 Posts
Posts: 138
Joined: 02 Mar 2009
Thanked: 15 times

### Re: warehouse

by life is a test » Sat Nov 14, 2009 6:49 pm
Testluv wrote:
Always think about what kind of info you would need to answer the question before approaching the statements. The question is asking us for the percent increase in (sofa) sales. This is a value (not a yes/no) question, so we need a single value for sufficiency. Either we need a special equation that relates the sales between the years, or else we actually need to know the sale prices and numbers sold in each year.

Statement One is immediately insufficient as it does not provide us with info about $. Statement Two is insufficient because we don't know the selling price of last year. There is no special equation relating sales, and we don't know the acutal sales for each year, or the number sold. Therefore, the answer is E. But, if at that point, you're not quite convinced, then: In combination: they sold 10% more sofas and at a rate that is$30 greater than last year. Don't resort to pure algebra here. Quickly pick two different numbers for last year's sale price (and for number sold), and you will see the answer changes. Because we can get multiple values, the statements, even after combination, are not sufficient to answer the question.

Choose E.
if the second statement had given a % increases or decrease is sales price rather than an absolute value increase then the ans would be C (providing statement 1 stayed the same)?

Thanks.

GMAT Instructor
Posts: 1302
Joined: 19 Oct 2009
Location: Toronto
Thanked: 539 times
Followed by:163 members
GMAT Score:800
by Testluv » Sat Nov 14, 2009 7:14 pm
if the second statement had given a % increases or decrease is sales price rather than an absolute value increase then the ans would be C (providing statement 1 stayed the same)?

Thanks.
Yes, in that case C would be the correct answer, and good point.
Kaplan Teacher in Toronto

Junior | Next Rank: 30 Posts
Posts: 23
Joined: 27 Jul 2010
Location: Washington, DC
GMAT Score:700
by saritalr » Tue Nov 02, 2010 9:06 am
Testluv wrote:
if the second statement had given a % increases or decrease is sales price rather than an absolute value increase then the ans would be C (providing statement 1 stayed the same)?

Thanks.
Yes, in that case C would be the correct answer, and good point.