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

 It is currently 16 Oct 2019, 22:33

### 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

# A consulting firm uses a Trenchard score to help companies determine

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58390
A consulting firm uses a Trenchard score to help companies determine  [#permalink]

### Show Tags

25 Jul 2017, 22:38
1
2
00:00

Difficulty:

55% (hard)

Question Stats:

62% (01:32) correct 38% (01:31) wrong based on 90 sessions

### HideShow timer Statistics

A consulting firm uses a Trenchard score to help companies determine which computer tasks work best together in parallel. The Trenchard score is calculated by determining the number of nanoseconds a task takes for each of two processes, then calculating the difference between the reciprocals of those times. The reciprocal of that difference is the Trenchard score. What would be the Trenchard score for tasks that take a and b nanoseconds, respectively, where b>a?

A. a−b

B. ab/(a−b)

C. ab/(b−a)

D. (a−b)/(ab)

E. (b−a)/(ab)

_________________
Senior PS Moderator
Joined: 26 Feb 2016
Posts: 3341
Location: India
GPA: 3.12
A consulting firm uses a Trenchard score to help companies determine  [#permalink]

### Show Tags

25 Jul 2017, 22:51
1
1
Trenchard score: Reciprocal of the difference of the reciprocals of times taken to complete a task

If we have time taken as T1 and T2,

Trechard score can be calculated as follows :
Step 1 : Difference in reciprocal of their times : $$\frac{1}{T1} - \frac{1}{T2} = \frac{(T2 - T1)}{(T1*T2)}$$
Step 2 : Reciprocal of difference in reciprocal of times : $$\frac{(T1*T2)}{(T2 - T1)}$$

Given data: Tasks take a and b nanoseconds respectively, with b>a

Substituting these values into the formula, the Trenchard score is $$\frac{a*b}{b-a}$$ (Option C)
_________________
You've got what it takes, but it will take everything you've got
Senior Manager
Joined: 29 Jun 2017
Posts: 424
GPA: 4
WE: Engineering (Transportation)
Re: A consulting firm uses a Trenchard score to help companies determine  [#permalink]

### Show Tags

08 Sep 2017, 02:32
Ans is C:

a nano secs and b nano secs

so first difference between the reciprocals

D = 1/a- 1/b
D= (b-a) /ab

Reciprocal of difference = R = 1/D => ab/(b-a)

Trenchard Score is Reciprocal = ab/(b-a)
_________________
Give Kudos for correct answer and/or if you like the solution.
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8085
Location: United States (CA)
Re: A consulting firm uses a Trenchard score to help companies determine  [#permalink]

### Show Tags

11 Sep 2017, 16:00
Bunuel wrote:
A consulting firm uses a Trenchard score to help companies determine which computer tasks work best together in parallel. The Trenchard score is calculated by determining the number of nanoseconds a task takes for each of two processes, then calculating the difference between the reciprocals of those times. The reciprocal of that difference is the Trenchard score. What would be the Trenchard score for tasks that take a and b nanoseconds, respectively, where b>a?

A. a−b

B. ab/(a−b)

C. ab/(b−a)

D. (a−b)/(ab)

E. (b−a)/(ab)

First, let’s calculate the difference between the reciprocals of the times:

1/a - 1/b = b/(ab) - a/(ab) = (b - a)/(ab)

Notice that since b > a, 1/a > 1/b (so we use 1/a - 1/b instead of 1/b - 1/a). Next, we can calculate the Trenchard score as follows:

1/[(b - a)/(ab)] = (ab)/(b - a)

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Intern
Joined: 24 Jul 2017
Posts: 43
Location: India
WE: Information Technology (Computer Software)
Re: A consulting firm uses a Trenchard score to help companies determine  [#permalink]

### Show Tags

12 Sep 2017, 03:47
Trenchard score = reciprocal of the difference of the reciprocals of two times
Given that two times are 'a' and 'b' where b>a

Hence, 1/a > 1/b
---> Reciprocal(1/a - 1/b) = Reciprocal{(b-a)/ab} = ab/(b-a)
Intern
Joined: 06 Sep 2018
Posts: 36
GMAT 1: 760 Q50 V44
GMAT 2: 740 Q48 V44
Re: A consulting firm uses a Trenchard score to help companies determine  [#permalink]

### Show Tags

02 Oct 2018, 15:11
Hello! Where is it mentioned that the score can't be negative? I mean, couldn't the Trenchard score be a negative value? Although I did it instinctively I really don't understand why we need to perform the calculations on that order... If anyone could help I'd be grateful!
Re: A consulting firm uses a Trenchard score to help companies determine   [#permalink] 02 Oct 2018, 15:11
Display posts from previous: Sort by

# A consulting firm uses a Trenchard score to help companies determine

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

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