Last visit was: 24 Apr 2024, 16:36 It is currently 24 Apr 2024, 16:36

Close
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
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.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Kudos
Math Expert
Joined: 02 Sep 2009
Posts: 92900
Own Kudos [?]: 618811 [43]
Given Kudos: 81588
Send PM
Most Helpful Reply
Intern
Intern
Joined: 11 Sep 2017
Posts: 7
Own Kudos [?]: 9 [5]
Given Kudos: 1
Send PM
General Discussion
Retired Moderator
Joined: 10 Oct 2016
Status:Long way to go!
Posts: 1144
Own Kudos [?]: 6119 [4]
Given Kudos: 65
Location: Viet Nam
Send PM
RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11169
Own Kudos [?]: 31890 [4]
Given Kudos: 290
Send PM
Re: Which of the following expresses the range of possible values for [#permalink]
1
Kudos
3
Bookmarks
Expert Reply
Bunuel wrote:
Which of the following expresses the range of possible values for t if 0 < |5t − 8| < 1?

A. 2/5 < t < 14/5
B. 2/5 < t < 9/5
C. 7/5 < t < 14/5
D. 7/5 < t < 9/5
E. 9/5 < t < 14/5


Whenever we have modulus of this kind, the value inside MOD will be NEGATIVE and positive both, so a range will take 0 also unless specified..

Here 5t-8 will be NEGATIVE , -1, at 7/5 and POSITIVE,1, at 9/5..
And 0 at 8/5

So the range becomes 7/5 to 9/5..
However it should not consist of 8/5..
And ans should be 7/5<T<9/5, where T is not equal to 8/5..
Manager
Manager
Joined: 22 Nov 2016
Posts: 205
Own Kudos [?]: 267 [3]
Given Kudos: 50
Concentration: Leadership, Strategy
Send PM
Re: Which of the following expresses the range of possible values for [#permalink]
2
Kudos
1
Bookmarks
|5t-8| < 1 or |5t-8| >0

Solving these we get,
\(t<\frac{9}{5}\) or \(t>\frac{7}{5}\) for the first equation

The second equation yields \(t >\frac{8}{5}\) or \(\frac{8}{5}>t\), which is nonsensical.

Hence answer is D
Current Student
Joined: 04 Sep 2017
Status:Booth 1Y
Posts: 278
Own Kudos [?]: 1162 [2]
Given Kudos: 228
Location: United States (IL)
Concentration: Technology, Leadership
GMAT 1: 690 Q44 V41
GMAT 2: 730 Q50 V38
GPA: 3.62
WE:Sales (Computer Software)
Send PM
Which of the following expresses the range of possible values for [#permalink]
1
Kudos
1
Bookmarks
broall wrote:
Bunuel wrote:
Which of the following expresses the range of possible values for t if 0 < |5t − 8| < 1?

A. 2/5 < t < 14/5
B. 2/5 < t < 9/5
C. 7/5 < t < 14/5
D. 7/5 < t < 9/5
E. 9/5 < t < 14/5


Solve for the inequality \(0 < |5t − 8| < 1\)

\(|5t − 8| > 0 \implies t \neq \frac{8}{5}\)

\(|5t − 8| < 1 \implies -1 < 5t-8 < 1 \implies 7 < 5t < 9 \implies \frac{7}{5} < t < \frac{9}{5}\)

It seems that there is no answer satisfied the inequality.

The answer will be D if the condition \(0 < |5t − 8|\) doesn't exist in the inequality.


Broall, how do you know to drop the modulus and make the outliers -1 and 1? For me, I originally came up with \(\frac{8}{5}\)<t<\(\frac{9}{5}\). I just added 8 to both sides and then divided by 5. What is wrong with this solution and how should I approach questions like this in the future?

Thanks,
Director
Director
Joined: 05 Mar 2015
Posts: 852
Own Kudos [?]: 860 [0]
Given Kudos: 45
Send PM
Re: Which of the following expresses the range of possible values for [#permalink]
Bunuel wrote:
Which of the following expresses the range of possible values for t if 0 < |5t − 8| < 1?

A. 2/5 < t < 14/5
B. 2/5 < t < 9/5
C. 7/5 < t < 14/5
D. 7/5 < t < 9/5
E. 9/5 < t < 14/5


if we put t=8/5 which is included in option A-D
then inequality doesnt hold

for E again value is greater than defined range 0 < |5t − 8| < 1

I m not getting the answer
Could any one help!!

Bunuel
is everything right with the Question??
Current Student
Joined: 04 Sep 2017
Status:Booth 1Y
Posts: 278
Own Kudos [?]: 1162 [0]
Given Kudos: 228
Location: United States (IL)
Concentration: Technology, Leadership
GMAT 1: 690 Q44 V41
GMAT 2: 730 Q50 V38
GPA: 3.62
WE:Sales (Computer Software)
Send PM
[#permalink]
rkishores051 wrote:
|5t-8|<1

You have to calculate this for the 2 situations of when 5t-8 is positive and when 5t-8 is negative

when 5t-8 is +ve, |5t-8| = 5t-8
therefore, 5t-8<1 => t<9/5

when 5t-8 is -ve, |5t-8| = -(5t-8)
therefore, -(5t-8)<1 => 5t-8>-1 => t>7/5

the direct step for this sort of problems

|x|<y, then -y<x<y
|x|>y, then -y>x>y


Great description, thanks man!
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 32655
Own Kudos [?]: 821 [0]
Given Kudos: 0
Send PM
Re: Which of the following expresses the range of possible values for [#permalink]
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.
GMAT Club Bot
Re: Which of the following expresses the range of possible values for [#permalink]
Moderators:
Math Expert
92900 posts
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne