Find their respective hourly ratesBaten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
Hi,Baten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
Hey Stuart,Stuart Kovinsky wrote:Hi,Baten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
this question is actually simpler than it looks. Let's just let 240 files = 1 job.
So, the question reads:
X can do 1 job in 4 hours and Y can do 1 job in 8 hours. How long does it take them to do 1 job working together?
Using the basic combined work formula:
Combined Time = (time a * time b)/(time a + time b)
= (4*8)/(4+8)
= 32/12
= 8/3
Hi,Gurpinder wrote:
Hey Stuart,
Just had a question. In a problem like this where the work being done by both things is the same (240 files), can you substitute 1 for the 240 in all problems like this?
Would it work if i just entered 240 instead of 1?
Thanks,
While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 480 files?
120 = 1/2 * 240 files, so the question is asking how long it takes to do 1/2 of a job instead of 1. Accordingly, we halve the result of the formula.While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 120 files?
While working alone at their respective constant rates, computer x processes 120 files in 4 hours and computer Y processes 360 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 360 files?
Ok. Thanks. But what will if total 540 files are given instead of 360. Will the formula work.Stuart Kovinsky wrote:Hi,Gurpinder wrote:
Hey Stuart,
Just had a question. In a problem like this where the work being done by both things is the same (240 files), can you substitute 1 for the 240 in all problems like this?
Would it work if i just entered 240 instead of 1?
Thanks,
whenever the time given is for the two people to do the same amount of work, you can use the formula to calculate how long it would take them to do that amount of work combined.
Some questions ask how long it would take them to do a different amount of work, so you have to do one extra calculation at the end. Some examples:
While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 480 files?
480 = 2 * 240 files, so the question is how long it takes to do 2 jobs instead of 1. Accordingly, we double the result of the formula.
120 = 1/2 * 240 files, so the question is asking how long it takes to do 1/2 of a job instead of 1. Accordingly, we halve the result of the formula.While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 120 files?
On the other hand, if the time given for each worker relates to a different amount of work, you can't just plug and play into the formula - you have to make adjustments first. For example:
While working alone at their respective constant rates, computer x processes 120 files in 4 hours and computer Y processes 360 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 360 files?
Here we can't simply substitute 4 and 8 into the formula, because computer x's time is for 120 files, which is only 1/3 of the job. So, before using the formula, we have to calculate how long it would take X to do a full job, i.e. 360 files.
360 is 3 times 120, so it will take 3 times as long. 4 hours * 3 = 12 hours for a full job. Now we can let X=12 and Y=8 and apply the formula.
As long as you make the appropriate adjustments, yes (i.e. you convert to "1 job").Baten80 wrote:
Ok. Thanks. But what will if total 540 files are given instead of 360. Will the formula work.
How would you convert 8/3 hours into 2hr in 40min (I forgot what steps you should take)????dtweah wrote:Find their respective hourly ratesBaten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
240/4= 60files/hr and 30 files/hr
Combine their hourly rates when they work together: 90files/hr.
So in 1 hr they would do 90 files when working together. Pay attention to UNITs when working these problems b/c they can point the way.
1hr/90 files. The number multiplying this fraction must be in units of FILES. ( Another way to ask this problem is HOW many Files would they be able to work in x hours. Here you would use 90files/hr and multiple by x hous so that hours cancel. You are just inverting the fraction to get the UNIT u want). Back to Problem.
240 files X 1/90files. File cancel file and u are left with desired hours.
24/9= 8/3 hours.
HelloStuart Kovinsky wrote:Hi,Baten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
this question is actually simpler than it looks. Let's just let 240 files = 1 job.
So, the question reads:
X can do 1 job in 4 hours and Y can do 1 job in 8 hours. How long does it take them to do 1 job working together?
Using the basic combined work formula:
Combined Time = (time a * time b)/(time a + time b)
= (4*8)/(4+8)
= 32/12
= 8/3
X's rate = w/t = 240/4 = 60 files per hour.Baten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
Thanks a lot GMATGuru.GMATGuruNY wrote:X's rate = w/t = 240/4 = 60 files per hour.Baten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
Y's rate = w/t = 240/8 = 30 files per hour.
When X and Y work together, their combined rate = 30+60 = 90 files per hour.
Time for X and Y together to complete 240 files = w/r = 240/90 = 24/9 = 8/3 hours.
8/3 hours = 2 2/3 hours = 2 hours, 40 minutes.
GMATGuruNY wrote:X's rate = w/t = 240/4 = 60 files per hour.Baten80 wrote:While working alone at their respective constant rates, computer x processes 240 files in 4 hours and computer Y processes 240 files in 8 hours. If all files processed by these computers are same size, how long would it take the two computers, working at the same time and at their respective constant rates, to process a total of 240 files?
Help in solving this task.
Y's rate = w/t = 240/8 = 30 files per hour.
When X and Y work together, their combined rate = 30+60 = 90 files per hour.
Time for X and Y together to complete 240 files = w/r = 240/90 = 24/9 = 8/3 hours.
8/3 hours = 2 2/3 hours = 2 hours, 40 minutes.
