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:

Re: If Δ and ∅ represent single digits in the correctly worked c [#permalink]

Show Tags

21 Aug 2013, 18:40

2

This post received KUDOS

Asifpirlo wrote:

If Δ and ∅ represent single digits in the correctly worked computation above, what is the value of Δ times ∅? A. 6 B. 10 C. 12 D. 15 E. 18

So we have 2X7 * Y14 = 80,698. Off the bat, I know that 200x400=80,000, so I immediately think it must be 414 and 207. I could calculate this out (to 85,698) but it would be a waste of time, since I know already that 4 and 0 can't be the combination given 0 isn't an answer choice. Therefore, Y must be 3. By this logic alone, I can eliminate B as it is not a multiple of 3.

For the other number, I do a quick estimate in my head, that 300 x 260 = 78,000. Given that 314 is a bit more than 300, our number must be less than 260. I try 314 x 257 and get 80,698. So 3 x 5 = 15, and D is the answer.

Re: If Δ and ∅ represent single digits in the correctly worked c [#permalink]

Show Tags

23 Aug 2013, 11:53

4

This post received KUDOS

1

This post was BOOKMARKED

Good question.

I solved using the basic approach to multiply the two 3 digit numbers.

Let triangle be ^ and Theta be @

then our question becomes 2^7 x @14 -------- 80,698

Doing basic multiplication.

2^7 x @14 -------- _ 8 7

--------- 98 (here 9 can be only achieved when 7 gets added to 2 which can only happen when ^ is 5 and 4 x 5 =20 plus carry 2 from 4x7).

Replacing ^ by 5.

257 x @14 -------- 1 0 2 8 2 5 7

--------- 6 9 8 (again 6 here will only be possible when 5 gets added to 1, which is only possible when 7 gets multiplied to 3 resulting in 1 and carry 2).

Hence @ = 3

There for the answer is 3 x 5 =15.
_________________

Re: If Δ and ∅ represent single digits in the correctly worked c [#permalink]

Show Tags

24 Aug 2013, 05:42

replacing delta symbol with a and phi symbol with b

Here 2a7*b14; 4*7=28, so 2 carried over; The next digit after multiplication is (4*a+1*7+2(carried over))=10m+9 => 4*a=0 or 4*a=10m; now only a=5 satisfies this. Look at the options only two are multiples of 5. So solve for third digit you get (4*2+a*1+7*b+2 (carried over))=10n+6; as a=5 =>9+7b=10n; only b=3 satisfies this

therefore D it is . I have used vedic multiplication here.
_________________

--It's one thing to get defeated, but another to accept it.

Re: If Δ and ∅ represent single digits in the correctly worked c [#permalink]

Show Tags

22 Jan 2014, 07:26

1

This post received KUDOS

vabhs192003 wrote:

Good question.

I solved using the basic approach to multiply the two 3 digit numbers.

Let triangle be ^ and Theta be @

then our question becomes 2^7 x @14 -------- 80,698

Doing basic multiplication.

2^7 x @14 -------- _ 8 7

--------- 98 (here 9 can be only achieved when 7 gets added to 2 which can only happen when ^ is 5 and 4 x 5 =20 plus carry 2 from 4x7).

Replacing ^ by 5.

257 x @14 -------- 1 0 2 8 2 5 7

--------- 6 9 8 (again 6 here will only be possible when 5 gets added to 1, which is only possible when 7 gets multiplied to 3 resulting in 1 and carry 2).

Hence @ = 3

There for the answer is 3 x 5 =15.

Well done, and actually once you know that one of the digits is 5 you can proceed to pick the only answer choice that is a multiple of 5

So there is only one option: X=5, Y=3 => Result = 15 => Choose D

how do you imply that Y<=3?

=> 2,070Y+100XY+14X=7,780 => Y<=3

I guess you search for the maximal value of Y (with x=1) which gives us a total value below 7,780. If y=4 the equation would be above the 7,780 no matter what value x is. So if y=3 you have a result below 7,780 giving "some space" for x.
_________________

Thank You = 1 Kudos B.Sc., International Production Engineering and Management M.Sc. mult., European Master in Management Candidate

Re: If Δ and ∅ represent single digits in the correctly worked c [#permalink]

Show Tags

03 Feb 2015, 04:12

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: If Δ and ∅ represent single digits in the correctly worked c [#permalink]

Show Tags

22 Aug 2016, 18:23

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.
_________________

Campus visits play a crucial role in the MBA application process. It’s one thing to be passionate about one school but another to actually visit the campus, talk...

Its been long time coming. I have always been passionate about poetry. It’s my way of expressing my feelings and emotions. And i feel a person can convey...

Marty Cagan is founding partner of the Silicon Valley Product Group, a consulting firm that helps companies with their product strategy. Prior to that he held product roles at...

Written by Scottish historian Niall Ferguson , the book is subtitled “A Financial History of the World”. There is also a long documentary of the same name that the...