GRE Prep 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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
If r > 0, s ≠ 1/2 and r = 3s +1/1-2s, then s=
[#permalink]
Updated on: 27 Dec 2018, 03:22
Updated on: 27 Dec 2018, 03:22
Expert Reply
2
Bookmarks
00:00
Question Stats:
86% (01:27) correct
13% (02:15) wrong based on 270 sessions
Hide Show timer Statistics
If \(r > 0\), s ≠ \(\frac{1}{2}\) and \(r = \frac{3s +1}{1-2s}\), then \(s=\)
A) \(\frac{3r}{12 +6r}\)
B) \(-\frac{2r}{3}\)
C) \(\frac{r-1}{3+2r}\)
D) \(\frac{2}{3} (1-r)\)
E) \(-\frac{1+r}{3}\)
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If r > 0, s ≠ 1/2 and r = 3s +1/1-2s, then s=
[#permalink]
15 Jun 2017, 13:41
15 Jun 2017, 13:41
1
1
Bookmarks
Carcass wrote:
If \(r > 0\), s ≠ \(\frac{1}{2}\) and \(r = \frac{3s +1}{1-2s}\), then \(s=\)
A) \(\frac{3r}{12 +6r}\)
B) \(\frac{-2r}{3}\)
C) \(\frac{r-1}{3+2r}\)
D) \(\frac{2}{3(1-r)}\)
E) \(\frac{-1+r}{3}\)
Given: \(r = \frac{3s +1}{1-2s}\)
Multiply both sides by (1 - 2s) to get: r(1 - 2s) = 3s + 1
Expand: r - 2rs = 3s + 1
NOTE: We want the s's on one side. So....
Add 2rs to both sides: r = 3s + 2rs + 1
Subtract 1 from both sides: r - 1 = 3s + 2rs
Factor right side: r - 1 = s(3 + 2r)
Divide both sides by (3 + 2r) to get: (r - 1)/(3 + 2r) = s
Answer:
Show: ::
C
Cheers,
Brent
Re: If r > 0, s ≠ 1/2 and r = 3s +1/1-2s, then s=
[#permalink]
02 May 2020, 03:08
02 May 2020, 03:08
1
Bookmarks
Plug in s = 1 in the RHS and calculate r. Then plug that r value in the options and see which option gives the value of s (1).
When we plug in s, we get 3(1) + 1 / 1 - 2(1) = 4 / -1 = -4.
Plug -4 in the options and see which option gives 1 as the answer.
When we plug in s, we get 3(1) + 1 / 1 - 2(1) = 4 / -1 = -4.
Plug -4 in the options and see which option gives 1 as the answer.
