BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

experts pls help

Expert replies
Source: — Problem Solving |

by Anurag@Gurome » Wed Jan 26, 2011 3:25 am
Ramit88 wrote:ANS C

my ans is coming C
my method
-48 = -6 X -8

whats the mistake m making..?
Your answer is coming as C and the answer is C too! :)
Only mistake is that is -48 is not equal to (-6)*(-8), it should be (-6)*(8).

Your method is also okay.
Here is another method...

If (t - 8) is a factor of (t² - kt - 48), then (t² - kt - 48) = (t - 8)*(Something)
Hence, if we take t = 8, then the expression must be equal to zero.

Therefore, (8² - 8k - 48) = 0
=> (64 - 8k - 48) = 0
=> 8k = 16
=> k = 2

The correct answer is C.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Join the discussion

by Ramit88 » Wed Jan 26, 2011 3:55 am
Anurag@Gurome wrote:
Ramit88 wrote:ANS C

my ans is coming C
my method
-48 = -6 X -8

whats the mistake m making..?
Your answer is coming as C and the answer is C too! :)
Only mistake is that is -48 is not equal to (-6)*(-8), it should be (-6)*(8).

Your method is also okay.
Here is another method...

If (t - 8) is a factor of (t² - kt - 48), then (t² - kt - 48) = (t - 8)*(Something)
Hence, if we take t = 8, then the expression must be equal to zero.

Therefore, (8² - 8k - 48) = 0
=> (64 - 8k - 48) = 0
=> 8k = 16
=> k = 2

The correct answer is C.

it was a typo anurag.. neways thank u soooooo much :)
Join the discussion