Forum Home > GMAT > Quantitative > Problem Solving (PS)
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.
Oct 1110:00 AM EDT
-11:00 AM EDT
Think a 100% GMAT Verbal score is out of your reach? Target Test Prep will make you think again! Our course uses techniques such as topical study and spaced repetition to maximize knowledge retention and make studying simple and fun.
Oct 0810:00 AM EDT
-11:59 PM EDT
For a limited time use code TAKE15 to save on prep. Valid on Complete Course, Advanced Course, Bootcamp Course, Tutoring, and the Executive Assessment Course. This discount ends October 28, 2024.
Oct 1009:00 AM PDT
-12:00 PM PDT
Are you ready to take the next step in your academic and professional journey? If you’re aspiring to join one of the top 15 MBA programs, we’ve got an exciting opportunity just for you! Welcome to the GMAT Club's Free Interview Prep Event
Oct 1010:00 AM EDT
-11:00 AM EDT
Have you ever wondered how to score a PERFECT 805 on the GMAT? Meet Julia, a banking professional who used the Target Test Prep course to achieve this incredible feat. Julia's story is nothing short of an inspiration.
Oct 1211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Oct 13
11:00 AM IST
-01:00 PM IST
Attend this session to evaluate your current skill level, learn process skills, and solve through tough Arithmetic questions
Joined: 20 Jan 2017
Posts: 35
Given Kudos: 15
Location: United States (NY)
Schools: CBS '20 (A)
GMAT 1: 610 Q34 V41
GMAT 2: 750 Q48 V44 
GPA: 3.92
Re: Working simultaneously and independently at an identical
[#permalink]
30 Jan 2017, 04:45
30 Jan 2017, 04:45
4
Kudos
1
Bookmarks
1) First let's set up an equation for the 4 machines and find a rate of each machine: \(4r*6=x; 4r=\frac{x}{6}, r=\frac{x}{6}*\frac{1}{4}, r=\frac{x}{24}\)
2) Now let's set up an equation for 3x units: let N be the number of machines, then \(N*\frac{x}{24}*4=3x; N*\frac{x}{6}=3x, N=\frac{3x}{x/6}=18\)
The correct answer is B.
2) Now let's set up an equation for 3x units: let N be the number of machines, then \(N*\frac{x}{24}*4=3x; N*\frac{x}{6}=3x, N=\frac{3x}{x/6}=18\)
The correct answer is B.
Re: Working simultaneously and independently at an identical
[#permalink]
05 Aug 2017, 14:34
05 Aug 2017, 14:34
1
Kudos
Expert Reply
ajit257
Working simultaneously and independently at an identical constant rate, 4 machines of a certain type can produce a total of x units of product P in 6 days. How many of these machines, working simultaneously and independently at this constant rate, can produce a total of 3x units of product P in 4 days?
A. 24
B. 18
C. 16
D. 12
E. 8
A. 24
B. 18
C. 16
D. 12
E. 8
This is a wonderful problem to make an educated guess on. Rates & work problems are great for guessing in general.
Four machines make a certain amount of stuff in 6 days. We want to make three times as much stuff. That means we need at least three times as many machines, unless we also get extra time! (We don't.) So, eliminate 8.
We also have fewer days to spend making the stuff than we did originally. So, we can't get away with just having three times as many machines. We need more than three times as many. Eliminate 12.
Do we need 24 machines, though? That's 6 times as many as we had before. If you have six times as many machines, and you're only trying to make three times as much stuff, you should need half as much time. But we needed 4 days, not 3. Eliminate 24.
Guess 16 or 18 and move on!
Re: Working simultaneously and independently at an identical constant rate
[#permalink]
17 Dec 2017, 16:15
17 Dec 2017, 16:15
1
Kudos
2
Bookmarks
Let’s say x=600 units of P. Then, there are 100 units produced per day (600/6).
And since there are 4 machines, each machine produces 25 units per day (100/4).
We want to know how many machines it takes to produce 3x. Since we assumed x is 600, 3x is 1800 units of P. There must be 450 units produced per day (1800/4). And because one machine produces 25 units per day we will need 18 machines (450/25).
Sent from my iPhone using GMAT Club Forum
And since there are 4 machines, each machine produces 25 units per day (100/4).
We want to know how many machines it takes to produce 3x. Since we assumed x is 600, 3x is 1800 units of P. There must be 450 units produced per day (1800/4). And because one machine produces 25 units per day we will need 18 machines (450/25).
Sent from my iPhone using GMAT Club Forum
