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 Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

I answered that "statement 1 alone is sufficient, but statement 2 alone is not sufficient.

The test said that each statement alone is sufficient.

How can this be? If X = 32 and Y = 35, then XY = 1120 but if X= 33 and Y = 34, then XY = 1122. They have the same 10's digit in each case, but not the same product.

Am I missing something obvious or is the answer wrong in gmatprep?

Re: The sum of positive integers X and Y is 77. What is xy? [#permalink]

Show Tags

08 Nov 2006, 11:23

2

This post received KUDOS

andrewnorway wrote:

Can someone explain this to me, its a data suff problem:

The sum of positive integers X and Y is 77. What is value of xy?

(1) X = Y+1

(2) X and Y have the same tens digit

I answered that "statement 1 alone is sufficient, but statement 2 alone is not sufficient.

The test said that each statement alone is sufficient.

How can this be? If X = 32 and Y = 35, then XY = 1120 but if X= 33 and Y = 34, then XY = 1122. They have the same 10's digit in each case, but not the same product.

Am I missing something obvious or is the answer wrong in gmatprep?

Thanks,

Andrew

32+35 is not equal to 77

There are only 2 numbers that add up to 77 and have the same 10 digits. They are 38 and 39. Therefore either statement is sufficient - D

St1:
x = y+1
so y+1+y = 77 --> can solve for y, then can solve for x and finally xy. Sufficient.

st2:
x and y have the same tens digit. We can rule out the tens digit 1,2,4,5-9 because that would require the other integer to take either a bigger or smaller value. The only value that works is 38,39. Since it's multiplication, we don't care if x took 38 or x took 39. xy will be the same. Sufficient.

Re: The sum of positive integers X and Y is 77. What is xy? [#permalink]

Show Tags

20 Aug 2013, 09:48

The question says that X and Y are two positive integers but solving statement 1 you will get X and Y as fractions. If the statement refutes the question data then what is the answer?

Re: The sum of positive integers X and Y is 77. What is xy? [#permalink]

Show Tags

20 Aug 2013, 09:58

4

This post received KUDOS

Expert's post

6

This post was BOOKMARKED

spjmanoli wrote:

The question says that X and Y are two positive integers but solving statement 1 you will get X and Y as fractions. If the statement refutes the question data then what is the answer?

Actually we don't get fractions.

The sum of positive integers x and y is 77. What is value of xy?

Given that \(x+y=77\) find the value of \(xy\).

(1) x = y + 1 --> \((y+1)+y=77\) --> \(y=38\) and \(x=39\) --> \(xy=39*38\). Sufficient.

(2) x and y have the same tens digit. In order the sum to be 77 the tens digit of of x and y must be 3, thus \(x=38\) and \(y=39\) or vise-versa, in either case \(xy=39*38\). Sufficient.

Re: The sum of positive integers X and Y is 77. What is xy? [#permalink]

Show Tags

24 Sep 2013, 02:46

Bunuel wrote:

spjmanoli wrote:

The question says that X and Y are two positive integers but solving statement 1 you will get X and Y as fractions. If the statement refutes the question data then what is the answer?

Actually we don't get fractions.

The sum of positive integers x and y is 77. What is value of xy?

Given that \(x+y=77\) find the value of \(xy\).

(1) x = y + 1 --> \((y+1)+y=77\) --> \(y=38\) and \(x=39\) --> \(xy=39*38\). Sufficient.

(2) x and y have the same tens digit. In order the sum to be 77 the tens digit of of x and y must be 3, thus \(x=38\) and \(y=39\) or vise-versa, in either case \(xy=39*38\). Sufficient.

Answer: D.

Hope this helps.

Questions says 10's digit same, but isn't it assumption that it should be 3? Like this we can assume anything and solve the question. _________________

Re: The sum of positive integers X and Y is 77. What is xy? [#permalink]

Show Tags

24 Sep 2013, 02:52

1

This post received KUDOS

Expert's post

honchos wrote:

Bunuel wrote:

spjmanoli wrote:

The question says that X and Y are two positive integers but solving statement 1 you will get X and Y as fractions. If the statement refutes the question data then what is the answer?

Actually we don't get fractions.

The sum of positive integers x and y is 77. What is value of xy?

Given that \(x+y=77\) find the value of \(xy\).

(1) x = y + 1 --> \((y+1)+y=77\) --> \(y=38\) and \(x=39\) --> \(xy=39*38\). Sufficient.

(2) x and y have the same tens digit. In order the sum to be 77 the tens digit of of x and y must be 3, thus \(x=38\) and \(y=39\) or vise-versa, in either case \(xy=39*38\). Sufficient.

Answer: D.

Hope this helps.

Questions says 10's digit same, but isn't it assumption that it should be 3? Like this we can assume anything and solve the question.

No. The tens digit of x and y cannot be any digit but 3: if it's less than 3, then x+y<77 and if it's greater than 3 then x+y>77.

Re: The sum of positive integers x and y is 77. What is value of [#permalink]

Show Tags

14 Feb 2014, 00:28

Nice question !

X+y=77

x=y+1

then x=39 and y=38 statement 1 is sufficient

statement 2---> same tens digit means both numbers are from 30 to 39 inclusive. so there is only two digits 38 and 39. sufficient

if it wud have been less 77.. for example 76 or 75..x+y=75 or x+y=76 then statement 2 wud have been insuffient. A trick is they have given 77..if we jump one number tens digit wud be 4. _________________

Bole So Nehal.. Sat Siri Akal.. Waheguru ji help me to get 700+ score !

Re: The sum of positive integers x and y is 77. What is value of [#permalink]

Show Tags

17 Jun 2015, 17:46

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________

Re: The sum of positive integers x and y is 77. What is value of [#permalink]

Show Tags

18 Jun 2016, 03:05

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________

Part 2 of the GMAT: How I tackled the GMAT and improved a disappointing score Apologies for the month gap. I went on vacation and had to finish up a...

So the last couple of weeks have seen a flurry of discussion in our MBA class Whatsapp group around Brexit, the referendum and currency exchange. Most of us believed...

This highly influential bestseller was first published over 25 years ago. I had wanted to read this book for a long time and I finally got around to it...