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

Redeem

Sum of 1000

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Fri Jan 02, 2009 5:12 pm
Brent,
The question doesnt say different digits so I am assuming that's something u wanted in the question for a purpose.

Under that assumption, coming to the problem:

Stmt II

eb = 24

8,3 6,4
CANT BE 8,3 HAS TO BE 6,4

CARRY OVER WILL BE 1

SO A+D has to be 9

c and f have both got to be 0 since eb=6,4

we can find the sum of the digits(one single value 19)

SUFF

Stmt I

333
667

444
556

INSUFF

I would go with B)
Top
User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Fri Jan 02, 2009 5:26 pm
Stmt I

333
667

444
556

INSUFF
I'm not sure about your analysis of statement (1).
In both examples, the sum of the digits is 28
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Fri Jan 02, 2009 5:37 pm
U r right; added it incorrectly. Got lucky with those numbers but since it said atleast 3 it opens up many possibilities so was trying to prove it as INSUFFICIENT. I have included a new set of numbers below

333
667

sum of digits = 28


444
556

sum of digits = 28

250
750

sum of digits = 19

Good problem! Whats the OA?
Top
User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Fri Jan 02, 2009 5:40 pm
Nice work - the answer is, indeed, B
Back to the drawing board :)
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pm
Thanked: 237 times
Followed by:25 members
GMAT Score:730

by logitech » Fri Jan 02, 2009 7:01 pm
Cramya, as much as I like your number plugging methods, I findthem quite risky sometimes.

100(a+b) +10 (c+d) + (e+f) = 1000

There are three scenarios:

1 ) 900 + 100 + 0

2) 900 + 90 + 10

3) 1000 + 0 + 0


Statement 1) At least three numbers are bigger than 3

This eliminates the 3rd scenario.

but we still can have the 1st and 2nd scenarious - INSUF

a+b = 9, c+d =10 , e+f = 0 => 19
a+b = 9, c+d =9 , e+f = 10 => 28

Statement 2) cd=24

So it can be 8x3 or 6x4

8,3 does not work because

100 x 9 + 10 x 11 = 900+110 > 1000

So it needs to be 6,4 ---> which is the first scenario

So the answer is Beautiful question
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Fri Jan 02, 2009 7:20 pm
Thanks Logtech! Like I always say we must always go with what we are most comfortable (conventional/unconventional) with, since that's the first line of attack we would be employing on the real exam.

Since I was tring to prove INSUFFCY of stmt I , I felt picking numbers was the best route to take at that time without spending too much time on the nitty gritties.

Also since I had done stmt II first all I had to show was the sum of the digits could vary with stmt I

For stm 1), I could have taken an example with 19 as the sum and then some random numbers that gives a different sum(satisfying atleast 3 condn).

Done...
Top
User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pm
Thanked: 237 times
Followed by:25 members
GMAT Score:730

by logitech » Fri Jan 02, 2009 7:33 pm
Cramya,

I wish I am as comfortable as you are with plugging numbers since I always feel like I am missing out something. But I am reading your solutions very carefully to understand your methods better.

I am constantly in search of bullet proof solutions which we can apply under 2 minutes.

Keep up the good work master,
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Fri Jan 02, 2009 7:37 pm
Logitech,

Thanks for the kind words! I always try to remember Ron's words of wisdom i.e. to not loose sight of whats in hand by trying to spend too much time on a textbook method(whats textbook for one may not be textbook method for the other...)

You too keep up the good work man! Some of the solutions u post are excellent too.

Good luck!

Regards,
CR
Top
Post new topic Post Reply
• Page 1 of 1