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GMAT Prep - DS Numbers

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GMAT Prep - DS Numbers

by oks » Fri Dec 26, 2008 3:58 pm
If K is a positive three-digit integer, what is the hundreds digit of K?

a. The hundreds digit of K+150 is 4
b. The tens digit of K+25 is 7

I got the correct answer of E, but my approach to solve this problem took more than 2 minutes. Could someone explain an easy way to solve this? Thanks.
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Source: — Data Sufficiency |
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by cramya » Fri Dec 26, 2008 4:38 pm
Other than picking numbers not sure if an algebric approach exists and is any easier.

Stmt I

250 + 150 = 4..

346 + 150 = 4..

INSUFF

Stmt II

250 + 25 = 275
346 + 25 = 371

INSUFF

Stmt I and II

use same numbers still INSUFF

Choose E)



Hi Oks,

Please post official answers using spoiler function so that other users dot not see the answer before they provide their solutions.


OA : E
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by vittalgmat » Sat Dec 27, 2008 10:55 pm
Same here, plugging number is probably faster than algebraic soln.
And in a timed situation, if we dont accurately record the time before starting problem, then the mind's clock runs faster or slower than actual cloc !! :).

Atleast, if u know that u will get the answer correctly, it is worth spending a few seconds more.
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