K is a two-digit number, if the sum of the tens and unit : PS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 17 Jan 2017, 09:35

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# K is a two-digit number, if the sum of the tens and unit

Author Message
SVP
Joined: 24 Sep 2005
Posts: 1890
Followers: 19

Kudos [?]: 291 [0], given: 0

K is a two-digit number, if the sum of the tens and unit [#permalink]

### Show Tags

05 Apr 2006, 07:53
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

K is a two-digit number, if the sum of the tens and unit digits is 3 less than the product of the two digits. What is the value of K?
Manager
Joined: 09 Feb 2006
Posts: 129
Location: New York, NY
Followers: 1

Kudos [?]: 7 [0], given: 0

### Show Tags

05 Apr 2006, 08:12
K is a two-digit number, if the sum of the tens and unit digits is 3 less than the product of the two digits. What is the value of K?

Let's set the tens digit as x and the units digit as y.

X+Y+3 = X*Y

I think that this then requires a slight bit of logic. X and Y need to be small because otherwise their product would be too great. After considering a couple of values, I can say that K is 33.

Is their a "foolproof" method to solving that equation? I realized that the equation could be set as x - xy + y = -3, but couldn't remember how to solve for x and y as a quadratic. Any thoughts?
Manager
Joined: 20 Nov 2004
Posts: 108
Followers: 0

Kudos [?]: 3 [0], given: 0

### Show Tags

05 Apr 2006, 08:34
K = 10A + B
A + B = A*B-3
A*B - A = B + 3
A*(B - 1) = B + 3
A = (B + 3)/(B - 1)

Then check the possible cases where both A and B
are integers. Start with B = 0 and end with B = 9.

This leads to 52, 33 and 25, so K cannot be determined.
Manager
Joined: 24 Oct 2005
Posts: 169
Followers: 35

Kudos [?]: 176 [0], given: 0

### Show Tags

05 Apr 2006, 09:22
I agree...k cannot be determined without further information.
VP
Joined: 29 Dec 2005
Posts: 1348
Followers: 10

Kudos [?]: 60 [0], given: 0

### Show Tags

05 Apr 2006, 11:27
yah, there are more than one solution, Laxi.

laxieqv wrote:
K is a two-digit number, if the sum of the tens and unit digits is 3 less than the product of the two digits. What is the value of K?

how about -30 [10(-3) + 0], since 3 is -ve and 0 cannot be -ve or +ve.

sum = -3
product = 0
diff = -3

though it is only an additional one but i am not sure how correct it is?
Senior Manager
Joined: 11 Nov 2005
Posts: 328
Location: London
Followers: 1

Kudos [?]: 11 [0], given: 0

### Show Tags

06 Apr 2006, 12:52
when K has several values,
given in the choice one can select the right answer.

ccax wrote:
K = 10A + B
A + B = A*B-3
A*B - A = B + 3
A*(B - 1) = B + 3
A = (B + 3)/(B - 1)

Then check the possible cases where both A and B
are integers. Start with B = 0 and end with B = 9.

This leads to 52, 33 and 25, so K cannot be determined.
06 Apr 2006, 12:52
Display posts from previous: Sort by

# K is a two-digit number, if the sum of the tens and unit

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.