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:

At a certain department store present-wrapping counter, each [#permalink]

Show Tags

08 Feb 2006, 01:16

13

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

95% (hard)

Question Stats:

41% (02:01) correct
59% (02:18) wrong based on 400 sessions

HideShow timer Statistics

At a certain department store present-wrapping counter, each clerk will wrap no fewer than twenty and no more than thirty presents per hour. If seventy people are standing in line, will all of their presents be wrapped after one hour?

(1) Each person in line has at least one present to be wrapped by one of the six clerks at the counter. (2) If each person in line had one more present to be wrapped, nine clerks would be required to guarantee that every present would be wrapped in one hour.

agree with C)
from stem we know that one clerk can wrap 30 gifts at most per hour. Seventy people on the line,
From A we know that there are six clerks and minimum 70 presents which is insufficient
From B) we can calculate the number of gifts in the people on the line 9x30=270-70=200 approx. but we do not know how many clerks are currently working
combining both it is clear that 270-70=200 presents hold the people in the line, currently there are 6 clerks working who can pack 30 gifts at most, so the clerks will not be able to complete the job in one hour

I actually find this question confusing. Please correct me if I'm wrong.

Combining (1) and (2) we know that:
if (2) assumes that a clerk can wrap 20 gifts per hour, then we have 9*20=180, but since the customers have 1 more, subtract 70 ->110
if (2) assumes that a clerk can wrap 30 gifts per hour, than we have 9*30=270, ->200

If there are six clerks and they work at 20 g/h, in the case of 110 they would be able to wrap all the gifts, otherwise they wouldn't.

Attachments

gifts.JPG [ 13.06 KiB | Viewed 4976 times ]

_________________

Please allow me to introduce myself: I'm a man of wealth and taste

Hi,
=======================================
At a certain department store present-wrapping counter, each clerk will wrap no fewer than 20 and no more than 30 presents per hour. If seventy people are standing in line, will all of their presents be wrapped after one hour?
=======================================
So the slowest clerk can wrap 20 gifts
As a worst case the number of gifts wrapped in an hour is
20 * number of clerks.

=======================================
(1) Each person in line has at least one present to be wrapped by one of the six clerks at the counter.
=======================================
This does not give the number of gifts, hence is insufficient.

=======================================
(2)If each person in line had one more present to be wrapped, nine clerks would be required to guarantee that every present would be wrapped in one hour.
=======================================
This means that if there are 70 more gifts, nine clerks are needed.
If you can guarantee that 9 slow clerks can wrap all gifts in an hour, you can pretty much say any combination of clerks, slow or fast can do it within an hour.

Total number of gifts + 70 <= 9clerks * 20 Gifts wrapped by each
Total number of gifts <= 180 - 70
<= 110

However (2) does not give the number of clerks at the counter, hence is insufficient.

Using (1) and (2) together -
Number of clerks = 6
Number of gifts <= 110

Assume all 6 clerks are slow; They can wrap 120 gifts in an hour.
Since we have 110 or less, this can be done.

This means that if there are 70 more gifts, nine clerks are needed. If you can guarantee that 9 slow clerks can wrap all gifts in an hour, you can pretty much say any combination of clerks, slow or fast can do it within an hour.

Total number of gifts + 70 <= 9clerks * 20 Gifts wrapped by each Total number of gifts <= 180 - 70 <= 110

However (2) does not give the number of clerks at the counter, hence is insufficient.

Using (1) and (2) together - Number of clerks = 6 Number of gifts <= 110

Assume all 6 clerks are slow; They can wrap 120 gifts in an hour. Since we have 110 or less, this can be done.

I'd say Answer is C.

I am lost on this one. Kaplan has a very similar solution noted too. However, instead of slowest case scenario, if I take the highest numbers: Total number of gifts + 70 <= 9clerks * 30 Gifts wrapped by each Total number of gifts <= 270 - 70 <= 200

Using (1) and (2) together - Number of clerks = 6 Number of gifts <= 200 Maximum gifts that can be wrapped 6 clerks: 6*30 = 180.

Which contradicts the slow case and so the answer to the main question will be E.

At a certain department store present-wrapping counter, each clerk will wrap no fewer than twenty and no more than thirty presents per hour. If seventy people are standing in line, will all of their presents be wrapped after one hour?

Say each clerk can wrap x presents per hour. We are given that \(20\leq{x}\leq{30}\).

(1) Each person in line has at least one present to be wrapped by one of the six clerks at the counter. From that we can get that the number of presents to be wrapped is at least 70 and that there are 6 clerks at the counter. Now, the number of presents 6 clerks can wrap in an hour is \(120\leq{x}\leq{180}\). Still not sufficient to answer the question: if the # of presents is 70, then the answer would be YES but if the # of presents is greater than 180, then the answer would be NO. Not sufficient.

(2) If each person in line had one more present to be wrapped, nine clerks would be required to guarantee that every present would be wrapped in one hour.

Say 70 people in line have total of n presents. We are told that n+70 presents can be wrapped by 9 clerks. 9 clerks can for sure wrap 9*20=180 presents. Thus we are given that \(n+70\leq{180}\) --> \(n\leq{110}\). So, there are at most 110 presents to be wrapped.

To guarantee wrapping 110 presents minimum 6 clerks are needed (6 slowest clerks can wrap 120 presents). We don't know how many clerks are there at the counter. Not sufficient.

(1)+(2) From (1) we know that there are 6 clerks, thus they can for sure wrap minimum 120 presents, since the # of presents is less than or equal 110, then these 6 can wrap all the presents. Sufficient.

Re: At a certain department store present-wrapping counter, each [#permalink]

Show Tags

20 Oct 2013, 11:27

2

This post received KUDOS

Thanks Bunuel What I don't understand is, why did you choose the minimum speed as opposed to maximum in your calculation for n You used: n+70 <= 180 Why not: n+ 70 <=270

The statement says 9 clerks can wrap n+70 presents at a speed of between 20...30 presents per hour. Why choose 20 and not 30? Is it because of the use of the word "guarantee" in statement 2?

Thanks Bunuel What I don't understand is, why did you choose the minimum speed as opposed to maximum in your calculation for n You used: n+70 <= 180 Why not: n+ 70 <=270

The statement says 9 clerks can wrap n+70 presents at a speed of between 20...30 presents per hour. Why choose 20 and not 30? Is it because of the use of the word "guarantee" in statement 2?

Absolutely. We need to guarantee that every gift will be wrapped, thus we must consider that the clerks work at the slowest possible rate.
_________________

Re: At a certain department store present-wrapping counter, each [#permalink]

Show Tags

05 Feb 2015, 14:36

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: At a certain department store present-wrapping counter, each [#permalink]

Show Tags

01 Apr 2016, 14:06

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.
_________________