Problem Solving/Data Questions I got wrong, please help

Problem Solving — algebra and arithmetic (GMAT Focus Edition)
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Source: — Quantitative Reasoning |

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by BuckeyeT » Mon Feb 09, 2009 6:29 pm
Hey Ellexay-

You might get a better response if you post these questions separately. Also, a few of these questions have been recently asked. I'd be happy to help when posted separately. Good luck with the test!

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by ellexay » Tue Feb 10, 2009 8:14 am
Thanks, Buckeye. I should do that then.

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by gmat740 » Mon Feb 16, 2009 11:26 pm
Hi,
I think for the first question,only the first answer is sufficient because even if a number in the list is even integer,that doesn't make that integer positive
Q2. $6 is to be divided among x(say) Cupcake(denoted by C) and y(let) Dognuts(denoted by D)
So we have
xC+ yD = 6
now option-1
3C-2D = 0.1
(2)Option
C + D =2x 0.35= 0.70

So combining both the equations,we get


C= $ 0.3
D = $ 0.4

however we need the value of y
which can not be calculated unless x(no of cupcakes) is given

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by gmat740 » Mon Feb 16, 2009 11:32 pm
Q3. Simple Unitary Method
Q4. Not very Clear

Q5. new price per ounce = P/80%of W

where,
W= Weight
P=Price
Initially

Price per Ounce = P/W

Change = P/0.8W - P/W=1/4P/W

Thus 25%

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by marouan » Tue Feb 17, 2009 10:01 am
Q 27:
Z*T < -3 : Z is it z < 4 ?

given that z*t < -3 means that the prodoct is negative.
1- z< 9 not helping alone because U need to kow about z!
2- t<-4 means that t is negative so as teh product of zt is negative so z is positive : 0< z
by adding (1) and (2) you will get that 0< z < 9
sttill not enough to solve the question so answer is E

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by marouan » Tue Feb 17, 2009 10:05 am
Q28:
20 positive integers .. how many are odd:

Answer:
(1)10 of the integers are even ==> teh reset is odd : You got the answer here
(2) 10 are multiple of 4
here your mind wil goes right a way like this: multiple of 4 imply that they are even ... so the rest is odd !! like (1) but this is wrong because the reset could be also even but not multiple of 4.. like 18 for exmple !!
SO (2) is not enough

answer is A

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by marouan » Tue Feb 17, 2009 10:12 am
Q 29:
I think here it's a trap, because he indicated that you have 3000 families but he swich after speaking of the memebers of the families taht they have cars and TVs ( OF the familes who lives on the town , 2980 own a car ==> you can have on teh same familie two member havng a car)
so as you are missing the family composition no one of the info is fear to answer the question.

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by marouan » Tue Feb 17, 2009 10:33 am
Q34:
Answer: the combination that you can get here is: ( jasgua, José) or (José, Jashua)
so result is (1/6* 1/5) +(1/6 *1/5) = 2/30 = 1/15
now say that yuo have 3 people out of 6 that they will interview..
the result will be 3!( 1/6 *1/5 *1/4).

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by marouan » Tue Feb 17, 2009 10:47 am
Q37: what percentage the faster machine delivered ?
Answer :
First machine Rate: k cartons by 8 hours => k/8 cartons in 1 Hour .
Second machine: Rate k cartons in 4 hours = k/4 cartons in 1 Hour.
Rate of the faster machine ( second one)= k/4 / ( k/4 + k/8)
remove k and it will gives you : 2/3 which is 66 2/3 %