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# maps and books

Author Message
Intern
Joined: 26 Feb 2011
Posts: 35

Kudos [?]: 120 [0], given: 1

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06 Mar 2011, 09:20
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/ 0.25
B/ 0.50
C/ 0.75
D/ 1.00
E/ 1.25

Kudos [?]: 120 [0], given: 1

Math Forum Moderator
Joined: 20 Dec 2010
Posts: 1964

Kudos [?]: 2051 [0], given: 376

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06 Mar 2011, 09:34
Cost per map: x
Cost per book: y

12x+10y=38;
72x+60y=228; multiply by 6

20x+15y=60
80x+60y=240; multiply by 4

Solving both equations;
72x+60y=228
80x+60y=240
- - -
-------------
-8x=-12
x=12/8=1.5

12x+10y=38;
12*1.5+10y=38
18+10y=38
y=20/10=2

Difference; y-x=2-1.5=0.5(Map sells for 50 cents less each)

Ans:"B"
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Kudos [?]: 2051 [0], given: 376

SVP
Joined: 16 Nov 2010
Posts: 1597

Kudos [?]: 592 [0], given: 36

Location: United States (IN)
Concentration: Strategy, Technology

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06 Mar 2011, 23:38
12x + 10y = 38 = 6x + 5y = 19 = 18x + 15y = 57

20x + 15y = 60 = 4x + 3y = 12 = 20x + 15y = 60

so x = 1.5

y = (19 - 9)/5 = 10/5 = 2

y - x = 0.5

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Kudos [?]: 592 [0], given: 36

Re: maps and books   [#permalink] 06 Mar 2011, 23:38
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