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word problem

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by sud21 » Sun Jan 15, 2012 2:22 am
Tom has x books and he can completely place them in the bookshelf by placing 10 copies in each line. If 10 more books are added in, he can completely place them in the bookshelf by placing 12 copies in each line. X=?
1). x<96
2). x>24
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Source: — Data Sufficiency |

by rijul007 » Sun Jan 15, 2012 5:27 am
sud21 wrote:Tom has x books and he can completely place them in the bookshelf by placing 10 copies in each line. If 10 more books are added in, he can completely place them in the bookshelf by placing 12 copies in each line. X=?
1). x<96
2). x>24
Number of lines = N
x = 10N

After adding 10 more books, Number of lines = M
x+10 = 12M

10N +10 = 12M
10(N+1)/12 = M
5(N+1)/6 = M
Value of (N,M) can be = (5,5), (11,10), (17,15), etc

X=?

1). x<96
10N<96
N<10
(5,5) agrees
X = 50
Suff

2). x>24
10N>24
N>2
Insuff


Option A
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by shekhar.kataria » Mon Jan 16, 2012 5:59 am
Value of (N,M) can be = (5,5), (11,10), (17,15), etc
@Rijul,

As far as what i can understand given the Question is that the no of selves will be same in any case. And in your explanation you have actually considered different shelf values.

Can anyone please help me clarify this thing. I am lost here.
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