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

Redeem

natural number

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 1578
Joined: Sun Dec 28, 2008 1:49 am
Thanked: 82 times
Followed by:9 members
GMAT Score:720

natural number

by maihuna » Mon Apr 20, 2009 7:18 am
the sum of all possible two digits number formed from three different one digit natural number when divided by the sum of original three numbers is equal to;


1. 18
2. 22
3. 36
4. 54
5. none
Top
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 93
Joined: Thu Apr 10, 2008 1:42 pm
Location: Chicago
Thanked: 20 times

by Musiq » Mon Apr 20, 2009 8:38 am
This is a hard question.... 700+, in my opinion...maybe even more.

Anyways here goes:

Let the 3 single digits be A , B and C.

The different 2 digit numbers that can be created are:
AB ------> The numerical value is 10*A + 1*B
BA ------> The numerical value is 10*B + 1*A
AC ------> The numerical value is 10*A + 1*C
CA ------> The numerical value is 10*C + 1*A
BC ------> The numerical value is 10*B + 1*C
CB ------> The numerical value is 10*C + 1*B

Add all these numbers to get (22*A ) + (22*B) + (22*C) as the value of the sum of all possible 2 digit numbers. This can be written as {22} {A +B+C)

We want to determine outcome when above is divided by {A+B+C}.

Answer is 22...or option B.
For love, not money.
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 435
Joined: Sat Sep 27, 2008 2:02 pm
Location: San Jose, CA
Thanked: 43 times
Followed by:1 members
GMAT Score:720

by dumb.doofus » Mon Apr 20, 2009 12:01 pm
I think the simplest way to do this question is plug in values..
just take 1,2 & 3

quickly write the numbers.. 12, 13, 21,23,31,32.. sum is 132 and so divide it by 6 i.e. 1+2+3

doesnt take much time.. answer 22
One love, one blood, one life. You got to do what you should.
https://dreambigdreamhigh.blocked/
https://gmattoughies.blocked/
Top
Senior | Next Rank: 100 Posts
Posts: 93
Joined: Thu Apr 10, 2008 1:42 pm
Location: Chicago
Thanked: 20 times

by Musiq » Mon Apr 20, 2009 12:10 pm
dumb.doofus wrote:I think the simplest way to do this question is plug in values..
just take 1,2 & 3

quickly write the numbers.. 12, 13, 21,23,31,32.. sum is 132 and so divide it by 6 i.e. 1+2+3

doesnt take much time.. answer 22
Picking numbers as a strategy immediately loses a LOT OF WIND as soon as one of the options reads " None of the above".

You can never be sure...unless of course, the question says "Which of the following COULD".

This is not a "COULD" but a "MUST" situation. I would highly recommend NOT picking numbers and instead learning the simple rules of digits.

Of course, this advise is only for those of us who are planning to take the test.

For the afficionados and the connoisseurs, my rant doesnt mean much. :D
For love, not money.
Top
Master | Next Rank: 500 Posts
Posts: 134
Joined: Sun Feb 15, 2009 7:44 pm
Thanked: 14 times

by m&m » Mon Apr 20, 2009 2:48 pm
you can actually do this question in your head, here's how:

digit 1= x
digit 2=y
digit 3=z

dividing by the sum you have:

x' = x/(x+y+z)
y' = x/(x+y+z)
z' = z/(x+y+z)


ignoring that we have a 2 digit number for a moment, we know that if we form groups of 2, each x', y', z' will get picked twice. so sum of all that is:

(2x + 2y + 2z)/(x+y+z) = 2

now we want to form a 2 digit number and the unit will be 2 and the tens will be 2. So 2*10 + 2*1 = 22
Top
Post new topic Post Reply
• Page 1 of 1