Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 27 Mar 2015, 20:07

### 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 w=60r+80s and r

Author Message
TAGS:
Director
Joined: 14 Sep 2005
Posts: 994
Location: South Korea
Followers: 2

Kudos [?]: 41 [0], given: 0

If r, s and w are positive numbers such that w=60r+80s and r [#permalink]  17 Nov 2005, 18:21
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If r, s and w are positive numbers such that w=60r+80s and r+s=1, is w < 70?

1) r > 0.5
2) r > s

--------------------------------------------------------------------------

Sorry for the confusion. I guess this question is messed-up.
Would it be ok if it were "numbers" instead of "integers" ?
_________________

Auge um Auge, Zahn um Zahn !

Last edited by gamjatang on 17 Nov 2005, 20:19, edited 1 time in total.
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5079
Location: Singapore
Followers: 21

Kudos [?]: 180 [0], given: 0

w = 60r + 80s

r+s = 1, then w = 60r + 80(1-r), w = 60r + 80 - 80r = w = 80-20r. In order for w to be greater than 70, it must be 71. So plug this in: 71 = 80 - 20r and r = 9/20. This value is less than 1/2. So if r is always greater than 1/2, w will always be less than 70. (1) is sufficient.

Statment (2) is a little contradicting. It says r>s, but we also know r and s are positive integers. Yet, r+s must be equal to 1. If so, s must be 0 but 0 is neither positive or negative. So i'm not too clear about (2).

Current Student
Joined: 28 Dec 2004
Posts: 3392
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 13

Kudos [?]: 180 [0], given: 2

how can r+s=1? the stem say both are positive integers?

this question is invalid in ma opinion..
SVP
Joined: 24 Sep 2005
Posts: 1895
Followers: 11

Kudos [?]: 133 [0], given: 0

Re: DS - Integers [#permalink]  17 Nov 2005, 20:05
gamjatang wrote:
If r,s and w are positive integers such that w=60r+80s and r+s=1, is w < 70?

1) r > 0.5
2) r > s

r+s=1 and r,s are positive integers ...it seems weird to me . Remember 0 is not a positive integer.
Current Student
Joined: 29 Jan 2005
Posts: 5244
Followers: 23

Kudos [?]: 175 [0], given: 0

Yup, this question is mindboggling
SVP
Joined: 05 Apr 2005
Posts: 1733
Followers: 5

Kudos [?]: 37 [0], given: 0

fresinha12 wrote:
how can r+s=1? the stem say both are positive integers?
this question is invalid in ma opinion..

good catch. r and s are only +ves to satisfy r+s=1.
good job freshina12.
Current Student
Joined: 29 Jan 2005
Posts: 5244
Followers: 23

Kudos [?]: 175 [0], given: 0

After the edit, my answer is D. Both are sufficient.
Current Student
Joined: 28 Dec 2004
Posts: 3392
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 13

Kudos [?]: 180 [0], given: 2

After edit...I would say D

(2) r>s

suppose r=0.99999999999999999999999 and s=0.000000000000000001

then in that case w~60...it is less than 70

suppose r=.50005 s=0.490005 then w~30+40~70...but we know it slightly less than 70...always...except when r and s both = 0.5 which is not the case
SVP
Joined: 24 Sep 2005
Posts: 1895
Followers: 11

Kudos [?]: 133 [0], given: 0

Re: DS - Integers [#permalink]  17 Nov 2005, 20:47
gamjatang wrote:
Edited: intergers -> numbers
--------------------------------------------------------------------------

If r, s and w are positive numbers such that w=60r+80s and r+s=1, is w < 70?

1) r > 0.5
2) r > s

--------------------------------------------------------------------------

Sorry for the confusion. I guess this question is messed-up.
Would it be ok if it were "numbers" instead of "integers" ?

you're correct, Matt ^_^
1) we have s=1-r --> w= 60r + 80 ( 1-r) = 80 - 20r
r>0.5 ---> 80-20r < 80 -20*0.5= 70
--->suff

2) r>s ---> r+r> r+s= 1 ---> 2r>1 ---> r>0.5 ---> similar to stmt 1 --->suff
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5079
Location: Singapore
Followers: 21

Kudos [?]: 180 [0], given: 0

ywilfred wrote:
w = 60r + 80s

r+s = 1, then w = 60r + 80(1-r), w = 60r + 80 - 80r = w = 80-20r. In order for w to be greater than 70, it must be 71. So plug this in: 71 = 80 - 20r and r = 9/20. This value is less than 1/2. So if r is always greater than 1/2, w will always be less than 70. (1) is sufficient.

Statment (2) is a little contradicting. It says r>s, but we also know r and s are positive integers. Yet, r+s must be equal to 1. If so, s must be 0 but 0 is neither positive or negative. So i'm not too clear about (2).

r > s

r+s = 1, so r and s could be (.9,.1) (.8,.2), (.7,.3), (.6,.4)
For each of these sets, w = 60r+80s gives 62, 64, 66, 68 all of which is less than 70.

So after the edit, answer should be D.
Similar topics Replies Last post
Similar
Topics:
4 If r, s, and w are positive numbers such that w = 60r + 80s 6 12 Sep 2010, 06:25
If r, s, and w are positive numbers such that x = 60r + 80s 11 03 Nov 2008, 21:13
If r, s, and w are positive numbers such that w = 60r + 80s 9 22 Jul 2008, 00:16
If r and s are positive numbers, and r+s=1, is r<s? (1) 1 19 Jan 2007, 08:49
R and M are positive even numbers. Is root (R*M) a positive 2 06 Sep 2006, 01:35
Display posts from previous: Sort by