GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Jun 2018, 08:42

### GMAT Club Daily Prep

#### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If r, s, and w are positive numbers such that x = 60r + 80s

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
VP
Joined: 30 Jun 2008
Posts: 1008
If r, s, and w are positive numbers such that x = 60r + 80s [#permalink]

### Show Tags

03 Nov 2008, 22:13
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

If r, s, and w are positive numbers such that x = 60r + 80s and r + s = 1, is x 0.5

(2) r > s

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

VP
Joined: 17 Jun 2008
Posts: 1479
Re: DS : is x < 70 ? [#permalink]

### Show Tags

03 Nov 2008, 22:31
D.

Going on a call....will post the explanation later.
SVP
Joined: 29 Aug 2007
Posts: 2426
Re: DS : is x < 70 ? [#permalink]

### Show Tags

03 Nov 2008, 23:48
amitdgr wrote:
If r, s, and w are positive numbers such that x = 60r + 80s and r + s = 1, is x < 70 ?

(1) r > 0.5
(2) r > s

x = 60r + 80s
x = 60r + 60s + 20s
x = 60 (r + s) + 20s
x = 60 + 20s

is s <0.5?

E. will explain later as well.

a quick question: what is the use of W?
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

SVP
Joined: 29 Aug 2007
Posts: 2426
Re: DS : is x < 70 ? [#permalink]

### Show Tags

03 Nov 2008, 23:50
scthakur wrote:
D.

Going on a call....will post the explanation later.

D?

I am really curious about your selection of D.

Probably you presummed +ve numbers as integers.

waiting for your explanation.
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

VP
Joined: 30 Jun 2008
Posts: 1008
Re: DS : is x < 70 ? [#permalink]

### Show Tags

04 Nov 2008, 00:10
GMAT TIGER wrote:
amitdgr wrote:
If r, s, and w are positive numbers such that x = 60r + 80s and r + s = 1, is x < 70 ?

(1) r > 0.5
(2) r > s

x = 60r + 80s
x = 60r + 60s + 20s
x = 60 (r + s) + 20s
x = 60 + 20s

is s <0.5?

E. will explain later as well.

a quick question: what is the use of W?

Thanks GMAT TIGER ... I did not rephrase the question, thats why I had problem

The question says --- r,s are Positive numbers

The question boils down to "is s <0.5?" as you showed....

(1) r > 0.5
if r + s = 1, then most definitely r and s have to be less than 1.
if r = 0.6 then s = 0.4 and s < 1
even if r = 0.9, s will be 0.1 and s< 1 .... sufficient

(2) r > s
if r + s = 1, then most definitely r and s have to be less than 1.
if r = 0.6 then s = 0.4 and s < 1
even if r = 0.9, s will be 0.1 and s< 1 .... sufficient

Thence D
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

VP
Joined: 17 Jun 2008
Posts: 1479
Re: DS : is x < 70 ? [#permalink]

### Show Tags

04 Nov 2008, 00:17
x = 60r + 80s = 80(r+s) - 20r = 80 - 20r.

From stmt1: r > 0.5 and 20r > 10
or -20r < -10
or 80-20r < 80-10
or, x < 70. Sufficient.

From stmt2:
r > s and since r + s = 1, r > (1-r) or 2r > 1 or r > 0.5 and this is the same as stmt1 and hence sufficient.
SVP
Joined: 29 Aug 2007
Posts: 2426
Re: DS : is x < 70 ? [#permalink]

### Show Tags

04 Nov 2008, 08:13
amitdgr wrote:
GMAT TIGER wrote:
amitdgr wrote:
If r, s, and w are positive numbers such that x = 60r + 80s and r + s = 1, is x < 70 ?

(1) r > 0.5
(2) r > s

x = 60r + 80s
x = 60r + 60s + 20s
x = 60 (r + s) + 20s
x = 60 + 20s

is s <0.5?

E. will explain later as well.

a quick question: what is the use of W?

Thanks GMAT TIGER ... I did not rephrase the question, thats why I had problem

The question says --- r,s are Positive numbers

The question boils down to "is s <0.5?" as you showed....

(1) r > 0.5
if r + s = 1, then most definitely r and s have to be less than 1.
if r = 0.6 then s = 0.4 and s < 1
even if r = 0.9, s will be 0.1 and s< 1 .... sufficient

(2) r > s
if r + s = 1, then most definitely r and s have to be less than 1.
if r = 0.6 then s = 0.4 and s < 1
even if r = 0.9, s will be 0.1 and s< 1 .... sufficient

Thence D

Since r + s = 1, (1) r > 0.5 and (2) r > s, what the **** I was looking for?

I completely forgot (r + s) = 1 after rephrasing.

Sorry guys, I am on break for a while for those silly mistakes..
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Current Student
Joined: 28 Dec 2004
Posts: 3293
Location: New York City
Schools: Wharton'11 HBS'12
Re: DS : is x < 70 ? [#permalink]

### Show Tags

04 Nov 2008, 08:30
yup D it is..

we know that X will always be less <70..
Manager
Joined: 30 Sep 2008
Posts: 111
Re: DS : is x < 70 ? [#permalink]

### Show Tags

05 Nov 2008, 04:19
amitdgr wrote:
If r, s, and w are positive numbers such that x = 60r + 80s and r + s = 1, is x < 70 ?

(1) r > 0.5

(2) r > s

The question <=> Is x < 70 <=> Is 60r + 80s < 70 <=> Is 60r + 80(1-r) < 70 <=> Is -20r < - 10 <=> Is r > 0.5

(1) suff
(2) insuff

Intern
Joined: 21 Aug 2008
Posts: 23
Re: DS : is x < 70 ? [#permalink]

### Show Tags

05 Nov 2008, 09:00
amitdgr wrote:
If r, s, and w are positive numbers such that x = 60r + 80s and r + s = 1, is x < 70 ?

(1) r > 0.5

(2) r > s

D

The only way x is >=70 is if s is .5 or more. We know from either (1) or (2) that is not the case, since r+s=1
Manager
Joined: 08 Aug 2008
Posts: 226
Re: DS : is x < 70 ? [#permalink]

### Show Tags

05 Nov 2008, 12:20
D.
when both r & s are 0.5 each x=70.

If r increases, it will tip the scale >70 and if s increases , it wil tip towards >70.

1) r>0.5 -> s<0.5, so x<70--suff
2) r>s --means the same--suff
Senior Manager
Joined: 21 Apr 2008
Posts: 265
Location: Motortown
Re: DS : is x < 70 ? [#permalink]

### Show Tags

05 Nov 2008, 15:09
D

x = 60+20s
x r>0.5
2. r+s =1 and s r>s

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: DS : is x < 70 ?   [#permalink] 05 Nov 2008, 15:09
Display posts from previous: Sort by

# If r, s, and w are positive numbers such that x = 60r + 80s

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.