Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2512:30 AM EDT
-01:30 AM EDT
At one point, she believed GMAT wasn’t for her. After scoring 595, self-doubt crept in and she questioned her potential. But instead of quitting, she made the right strategic changes. The result? A remarkable comeback to 695. Check out how Saakshi did it.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
21 Feb 2018, 01:06
Kudos
Bookmarks
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
88% (02:21) correct
13%
(02:39)
wrong
based on 160
sessions
History
Date
Time
Result
Not Attempted Yet
Machine P can produce x widgets in 10 hours, Machine Q can produce x widgets in 6 hours, and Machine R can produce 2x widgets in 15 hours. If the three machines work together but independently, without interruption, how much time, expressed in hours, will be needed for them to produce 5x widgets?
A. 7 2/3
B. 8
C. 10 2/3
D. 12 1/2
E. 23 1/2
A. 7 2/3
B. 8
C. 10 2/3
D. 12 1/2
E. 23 1/2
21 Feb 2018, 03:37
Kudos
Bookmarks
Bunuel
x in 10 hours i.e in 1 hour x/10
x in 6 hours i.e in 1 hour x/6
x in 7.5 hours i.e in 1 hour x/7.5
widgets produced by machines combined in one hour = x/10 + x/6 + x/7.5 = 6+10+8/60 x = 24/60x = 2/5x
In one hour 2/5 x of widgets done
so in 5 hours 2x of widgets done
for 5x widgets 5x5/2 = 12 1/2
(D) imo
21 Feb 2018, 12:03
Kudos
Bookmarks
Bunuel
Find combined rate (add rates), then divide work by rate to get time.
Rate of P: \(\frac{x}{10}\)
Rate of Q: \(\frac{x}{6}\)
Rate of R: \(\frac{2x}{15}\)
All units are in hours. No need to write "units/hour." Time will be in hours.
Combined rate
= \(\frac{x}{10}+\frac{x}{6}+\frac{2x}{15}\)
Use LCM = 30
\(\frac{x}{10}+\frac{x}{6}+\frac{2x}{15}\)
\((\frac{3x}{30}+\frac{5x}{30}+\frac{4x}{30})=\frac{12x}{30}=\frac{6x}{15}=\)Combined rate
Time needed to produce 5x widgets?
\(W= 5x\), \(R*T = W\), and \(T= \frac{W}{R}\)
\(T =\frac{5x}{\frac{6x}{15}}=(5x*\frac{15}{6x})=\frac{75}{6}=\frac{25}{2}=12\frac{1}{2}\) hrs
Answer D
