• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Reach higher with Artificial Intelligence. Guaranteed
Now free for 30 days

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

## Difficult Math Problem #98 - Algebra

This topic has 4 member replies
800guy Master | Next Rank: 500 Posts
Joined
27 Jun 2006
Posted:
354 messages
Followed by:
5 members
11

#### Difficult Math Problem #98 - Algebra

Fri Feb 16, 2007 11:28 am
The numbers x and y are three-digit positive integers, and x + y is a four-digit integer. The tens digit of x equals 7 and the tens digit of y equals 5. If x < y, which of the following must be true?

I. The units digit of x + y is greater than the units digit of either x or y.
II. The tens digit of x + y equals 2.
III. The hundreds digit of y is at least 5.

A. II only

B. III only

C. I and II

D. I and III

E. II and III

from diff math doc. oa coming after a few people reply. have a nice weekend!!

800guy Master | Next Rank: 500 Posts
Joined
27 Jun 2006
Posted:
354 messages
Followed by:
5 members
11
Mon Feb 19, 2007 8:14 am
oa:

x= abc
y= def

x = a7c
y= b5f

x > y and x+y = wxyz.

I. The units digit of x + y is greater than the units digit of either x or y.

It can carryover one digit. False

II. The tens digit of x + y equals 2.

It can be 2 or 3. False

III. The hundreds digit of y is at least 5.

a+b+1 >= 10
a >b so a at least 5. True.

Ans: b

guynoor Senior | Next Rank: 100 Posts
Joined
10 Feb 2007
Posted:
59 messages
1
Fri Feb 16, 2007 1:51 pm
guynoor wrote:
800guy wrote:
The numbers x and y are three-digit positive integers, and x + y is a four-digit integer. The tens digit of x equals 7 and the tens digit of y equals 5. If x < y, which of the following must be true?

I. The units digit of x + y is greater than the units digit of either x or y.
II. The tens digit of x + y equals 2.
III. The hundreds digit of y is at least 5.

A. II only

B. III only

C. I and II

D. I and III

E. II and III

from diff math doc. oa coming after a few people reply. have a nice weekend!!
Suppose X = 275 and Y = 955
X + Y = 1230
Checking conditions in the answer choices........

banona Senior | Next Rank: 100 Posts
Joined
30 Dec 2006
Posted:
38 messages
1
Fri Feb 16, 2007 12:59 pm
The numbers x and y are three-digit positive integers,
this can be translated to : x = X1X2X3 ; AND y= Y1Y2Y3

* AS x + y is a four-digit integer. This only means that (Y1+X1+1 ) > 10; PROVIDED that y>x; then hundreds digis of y is superior to hundreds digit of x; so the inequality in Blod becomes 2y>9. Then easily Y> ou equal to 5. ( III is true)

* The tens digit of x equals 7 and the tens digit of y equals 5. If x < y, we can not conclude that ten digits of the sum is 2 as it depends on the unit digits of x and y. So II is not true

* Units digit of x + y can be greater than units digit of either x or y but it's not necessary. Fr this, consider three digit numbers x= 552 and y= 579 . It's obvious that the unit digit of the sum is 1 and is inferior to the unit digit of both numbers;

III. The hundreds digit of y is at least 5. only this one is true

B. III only s the naswer

Looking for feedback

_________________
I appologize for my Frenchy-English.
I am working on it.

guynoor Senior | Next Rank: 100 Posts
Joined
10 Feb 2007
Posted:
59 messages
1
Fri Feb 16, 2007 1:46 pm
See Below

Last edited by guynoor on Fri Feb 16, 2007 1:51 pm; edited 1 time in total

### Best Conversation Starters

1 lheiannie07 76 topics
2 LUANDATO 59 topics
3 ardz24 52 topics
4 AAPL 46 topics
5 M7MBA 45 topics
See More Top Beat The GMAT Members...

### Most Active Experts

1 Jeff@TargetTestPrep

Target Test Prep

141 posts
2 Brent@GMATPrepNow

GMAT Prep Now Teacher

136 posts
3 GMATGuruNY

The Princeton Review Teacher

134 posts
4 Rich.C@EMPOWERgma...

EMPOWERgmat

129 posts
5 Scott@TargetTestPrep

Target Test Prep

110 posts
See More Top Beat The GMAT Experts