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• ### $450 Tuition Credit & Official CAT Packs FREE November 15, 2018 November 15, 2018 10:00 PM MST 11:00 PM MST EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth$100 with the 3 Month Pack ($299) # GMAT paper test...looking for answer  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message Intern Joined: 30 Dec 2009 Posts: 10 GMAT paper test...looking for answer [#permalink] ### Show Tags 24 Feb 2010, 11:20 1 00:00 Difficulty: (N/A) Question Stats: 70% (01:41) correct 30% (02:20) wrong based on 25 sessions ### HideShow timer Statistics A certain store sells all maps at one price and all books at another price. On Monday the store sold 12 maps and 10 books for a total of$38.00 and on Tuesday the store sold 20 maps and 15 books for a total of $60.00. At this store, how much less does a map sell for than a book? a.$.25
b. $.50 c.$.75
d. $1.00 e.$1.25

I am brain dead on how to solve this. Thanks!

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Senior Manager
Joined: 25 Jun 2009
Posts: 279

### Show Tags

24 Feb 2010, 11:36
1
l02g060 wrote:
A certain store sells all maps at one price and all books at another price. On Monday the store sold 12 maps and 10 books for a total of $38.00 and on Tuesday the store sold 20 maps and 15 books for a total of$60.00. At this store, how much less does a map sell for than a book?

a. $.25 b.$.50
c. $.75 d.$1.00
e. $1.25 I am brain dead on how to solve this. Thanks! Lets assume the price of a map = x and price of the book = y Now 12x + 10y = 38 = > 6x +5y = 19 -- (a) 20x + 15 y = 60 -- (b) Multiplying (a) with 3 we get 18x + 15y = 57 -- (c) Solving these 2 equations ( b and c) we get x = 1.5 y =2 Manager Joined: 26 May 2005 Posts: 190 Re: GMAT paper test...looking for answer [#permalink] ### Show Tags 24 Feb 2010, 11:40 12m + 10b = 38 (m and b are price of one map and one book respectively) 20m + 15b = 60 b-m? solving we get m =$1.5, b = $2 and b-m = 0.5 B Manager Joined: 01 Feb 2010 Posts: 234 Re: GMAT paper test...looking for answer [#permalink] ### Show Tags 24 Feb 2010, 22:07 l02g060 wrote: A certain store sells all maps at one price and all books at another price. On Monday the store sold 12 maps and 10 books for a total of$38.00 and on Tuesday the store sold 20 maps and 15 books for a total of $60.00. At this store, how much less does a map sell for than a book? a.$.25
b. $.50 c.$.75
d. $1.00 e.$1.25

I am brain dead on how to solve this. Thanks!

Map at rate x
books at rate y
12x+10y = 38
20x+15y = 60

solving both x=3/2 = 1.5
y=2
y-x = .5 hence B.
Intern
Joined: 30 Dec 2009
Posts: 10

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24 Feb 2010, 22:28
chix475ntu wrote:
12m + 10b = 38 (m and b are price of one map and one book respectively)
20m + 15b = 60
b-m?

solving we get m = $1.5, b =$2 and b-m = 0.5

B

Do you prefer solving by addition as in prior answer or by substitution? Which works better on more diffuicult question sets?
Manager
Joined: 10 Feb 2010
Posts: 160

### Show Tags

26 Feb 2010, 19:44
[quote="l02g060] Do you prefer solving by addition as in prior answer or by substitution? Which works better on more diffuicult question sets?[/quote]

Sometimes it is easier to solve than substitute each value.

For substitution, it will be helpful if you can eliminate some of the answers choices.
Manager
Joined: 26 May 2005
Posts: 190

### Show Tags

26 Feb 2010, 20:08
l02g060 wrote:
chix475ntu wrote:
12m + 10b = 38 (m and b are price of one map and one book respectively)
20m + 15b = 60
b-m?

solving we get m = $1.5, b =$2 and b-m = 0.5

B

Do you prefer solving by addition as in prior answer or by substitution? Which works better on more diffuicult question sets?

I usually solve the problem then look at the solution. And also will try to substitute the answer in the equations(more likely for inequalities). If there are only few variables to work with, its will be much faster to solve than to substitute the answers. And for the difficult problems, you need to work on writing the given sentences into equations(once you can do that in a minute, you are good to go ) - rest would be easy to solve.
Intern
Joined: 06 Nov 2011
Posts: 35
Location: Germany
Concentration: Entrepreneurship, General Management
GMAT Date: 03-10-2012
GPA: 3

### Show Tags

13 Nov 2011, 06:24
Got 0.5 Dollar after 2:30 min.
Is that a 600points range question or more?
Intern
Joined: 24 Feb 2011
Posts: 28

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29 Nov 2011, 18:33
I can get to the 2 equations, but i can't solve them
where do you get the x=3/2 ?
Manager
Joined: 08 Sep 2011
Posts: 59
Concentration: Finance, Strategy

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08 Dec 2011, 09:57
I also got B but it took me a little over 2 mins

olivite wrote:
I can get to the 2 equations, but i can't solve them
where do you get the x=3/2 ?

your two equations are (when simplified):

1) 6m+5b=19
2) 4m+3b=12

I'll take the second one and solve for m and you get

m=3-(3/4b)

plug that into the first equation
6(3-(3/4b))+5b=19 --> 18-(18/4b)+5b=19 --> (-18/4b)+5b=1 ----> 1/2b=1 ---> b=2

now that we know b=2 plug that into either equation

4m+3(2)=12 ---> 4m=6---> m= 3/2 or 1.5

b-m=.5

hope that helps
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8527
Location: Pune, India

### Show Tags

09 Dec 2011, 02:38
l02g060 wrote:
chix475ntu wrote:
12m + 10b = 38 (m and b are price of one map and one book respectively)
20m + 15b = 60
b-m?

solving we get m = $1.5, b =$2 and b-m = 0.5

B

Do you prefer solving by addition as in prior answer or by substitution? Which works better on more diffuicult question sets?

More often than not, solving the equations simultaneously will give you the answer quickly. Solving by substitution is generally more painful with two equations in two variables.

Bring down your equations to lowest form:

1) 6m+5b=19
2) 4m+3b=12

Now, one way is to multiply the first equation by 3 and the second one by 5. But we see that the calculations involved are a little painful. It can be helpful if you are a little more resourceful with your numbers.

Say, I multiply the second equation by 1.5.
I get: 6m + 4.5b = 18

Now solve them simultaneously:
6m+5b=19
6m + 4.5b = 18

.5b = 1
b = 2
m = 1.5
b-m = .5
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Manager
Joined: 25 May 2011
Posts: 121

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11 Dec 2011, 01:04
Just solve these 2 equations:

$$6m+5b=19$$
$$4m+3b=12$$

B
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Re: GMAT paper test...looking for answer &nbs [#permalink] 30 Oct 2018, 05:11
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# GMAT paper test...looking for answer

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