ref. DS-79 OG 12

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ref. DS-79 OG 12

by nafiul9090 » Wed Mar 23, 2011 9:04 am
Leo can buy a certain computer for p1 dollars in State
A, where the sales tax is t1 percent, or he can buy the
same computer for p2 dollars in State B, where the
sales tax is t2 percent. Is the total cost of the
computer greater in State A than in State B ?
(1) t1 > t2
(2) p1t1 > p2t2


can anyone explain better this problem????
Source: — Problem Solving |

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by force5 » Wed Mar 23, 2011 9:13 am
Leo can buy a certain computer for p1 dollars in State
A, where the sales tax is t1 percent, or he can buy the
same computer for p2 dollars in State B, where the
sales tax is t2 percent. Is the total cost of the
computer greater in State A than in State B ?
(1) t1 > t2
(2) p1t1 > p2t2
IMO- E

total cost in state A = P1+p1*t1/100
in B P2+ p2*t2/100
now to find which cost is greater we should have two variables

Stmnt 1 says t1>t2 (insufficient)- since we dont know p1 and p2
stmnt 2 p1t1>p2t2 ( we still need p1 and p2)

combining-- if p1t1>p2p2 and t1>t2 even then we cant say what p1 and p2 can be ( ex- p1=8 and t1= 2 and p2= 4 and t2=1 .... in this case p1t1>p2t2 and t1>t2 however p1>p2)
in other case-- p1= 2 t1= 5 and p2=8 and t2=1 ........p1t1>p2t2 and t1>t2 however p1<p2....)
Hence E

Hope it helps.............

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by GMATGuruNY » Wed Mar 23, 2011 10:05 am
nafiul9090 wrote:Leo can buy a certain computer for p1 dollars in State
A, where the sales tax is t1 percent, or he can buy the
same computer for p2 dollars in State B, where the
sales tax is t2 percent. Is the total cost of the
computer greater in State A than in State B ?
(1) t1 > t2
(2) p1t1 > p2t2


can anyone explain better this problem????
Is A>B?

We can plug in values that satisfy the conditions given.

Statement 1: t1 > t2
No information about p1 and p2, so no way to compare A and B.
Insufficient.

Statement 2: p1t1 > p2t2
Let p1 = 100 and t1 = 20, so that p1t1 = 100*20 = 2000.
Let p2 = 100 and t2 = 10, so that p2t2 = 100*10 = 1000.
A = p1 + (t1% of p1) = 100 + (20% of 100) = 120.
B = p2 + (t2% of p2) = 100 + (10% of 100) = 110.
A>B.

Let p1 = 100 and t1 = 20, so that p1t1 = 100*20 = 2000.
Let p2 = 110 and t2 = 10, so that p2t2 = 110*10 = 1100.
A = p1 + (t1% of p1) = 100 + (20% of 100) = 120.
B = p2 + (t2% of p2) = 110 + (10% of 110) = 121.
A<B.
Since A>B in the first case and A<B in the second case, insufficient.

Statements 1 and 2 together:
The combinations used under statement 2 also satisfy statement 1, since in each case t1 > t2.
Thus, even when both statements are satisfied, it is possible that A>B and that A<B.
Insufficient.

The correct answer is E.
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by nafiul9090 » Wed Mar 23, 2011 5:14 pm
thnks guys....now its clear

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by bynddrvn » Thu Sep 01, 2011 8:49 am
Good explanation.

Just to be clear, the Official Guide 12th edition is misprinted, yes? In my book on p315 it says P1(1+ T1/0)? I believe it should be P1(1+ T1/100).