It is currently 11 Dec 2018, 07:20
My Tests

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.

Wendy can build a birdhouse in 15 hours and Miguel can build

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4749
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 93

Kudos [?]: 1653 [0], given: 396

CAT Tests
Wendy can build a birdhouse in 15 hours and Miguel can build [#permalink] New post 18 Jun 2018, 14:46
Expert's post
00:00

Question Stats:

75% (00:48) correct 25% (00:25) wrong based on 8 sessions
Wendy can build a birdhouse in 15 hours and Miguel can build an identical birdhouse in 10 hours. How many hours will it take Wendy and Miguel, working together at their respective constant rates, to build a birdhouse? (Assume that they can work on the same birdhouse without changing each other’s work rate.)

(A) 5
(B) 6
(C) 7
(D) 8
(E) 9
[Reveal] Spoiler: OA

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Director
Director
Joined: 20 Apr 2016
Posts: 756
Followers: 6

Kudos [?]: 511 [0], given: 94

CAT Tests
Re: Wendy can build a birdhouse in 15 hours and Miguel can build [#permalink] New post 02 Jul 2018, 05:07
sandy wrote:
Wendy can build a birdhouse in 15 hours and Miguel can build an identical birdhouse in 10 hours. How many hours will it take Wendy and Miguel, working together at their respective constant rates, to build a birdhouse? (Assume that they can work on the same birdhouse without changing each other’s work rate.)

(A) 5
(B) 6
(C) 7
(D) 8
(E) 9



A and B working together can complete a work in = \(\frac{(A*b)}{(A+B)}\)

Wendy and Miguel working together can finish the work in = \(\frac{(15*10)}{(15+10)}\) \(=\frac{150}{25} = 6 hrs\)
_________________

If you found this post useful, please let me know by pressing the Kudos Button

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4749
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 93

Kudos [?]: 1653 [0], given: 396

CAT Tests
Re: Wendy can build a birdhouse in 15 hours and Miguel can build [#permalink] New post 07 Jul 2018, 04:43
Expert's post
Explanation

Use two separate lines in a W = RT chart, one for Wendy and one for Miguel, to calculate their respective rates. Building 1 birdhouse equals doing 1 unit of work:

Attachment:
image1.jpg
image1.jpg [ 27.92 KiB | Viewed 282 times ]


Thus, Wendy’s rate is \(\frac{1}{15}\) birdhouses per hour, and Miguel’s rate is \(\frac{1}{10}\)birdhouses per hour. Since Wendy and Miguel are working together, add their rates:

Attachment:
image2.jpg
image2.jpg [ 23.85 KiB | Viewed 282 times ]


Now solve for t by first combining the fractions:

\(1=(\frac{1}{15}+\frac{1}{10})t\)

\(1=(\frac{5}{30})t\)

\(t=6\)
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Re: Wendy can build a birdhouse in 15 hours and Miguel can build   [#permalink] 07 Jul 2018, 04:43
Display posts from previous: Sort by

Wendy can build a birdhouse in 15 hours and Miguel can build

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.