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Work problem

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Work problem

by Veronica » Sat Sep 18, 2010 8:08 pm
15 programmers, working in a constant pace, finish a web page in 3 days. If after one day, 9 programmers quit, how many more days are needed to finish the remainder of the job?

a. 2; b.4; c.5; d.6; e.8

I solve this problem as follows:

15 programmers: 3 days: 1 web
-> 15 programmers: 1 day: 1/3 web
-> 15 programmers: 2 day: 2/3 web
-> 6 programmers: 5 day: 2/3 web

Therefore, 5-2 = 3 days more are needed to finish the remainder of the job

But in the answer key, no choice of 3, and the key is 5

Please show me whether I right, if not, what is my mistake??

Thank you!
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by HPengineer » Sat Sep 18, 2010 8:28 pm
There are some good solutions to this problem in the following post..

https://www.beatthegmat.com/java-guys-t55628.html

I like to solve these problems by multiplying the number of workers by the days it takes them to complete a job...

so for this problem 15 workers * 3 = 45 then because they say the 15 workers worked for 1 day we can take away 15.

So 45-15 now we have 30 items if you will to be completed by 6 workers... So 30/6 = 5
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by gmat1011 » Sat Sep 18, 2010 9:42 pm
I would set it up this way:

15 prog do 1/3 of the work in 1 day

1 prog does 1/3x15 = 1/45 of the work in 1 day


All 15 worked the first day so 15/45 of the work got done +> 1/3 of the work was done and 2/3 was left for the 2nd day onwards

But then 9 quit; so 6 prog had to do 2/3 of the work in how many more days after the first day to finish the remainder (2/3) of the job?

1/45 x 6 x D = 2/3

=> D = 2/18 x 45 = 5

If the question had been how many more days would be required to finish the job compared to the initial work plan or something to that effect then the answer would be 3; coz it took 6 days to finish the job (1+5) after 9 prog. left, in stead of just 3 days under the initial work plan when all 15 were working...
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by GMATGuruNY » Sun Sep 19, 2010 3:22 am
Veronica wrote:15 programmers, working in a constant pace, finish a web page in 3 days. If after one day, 9 programmers quit, how many more days are needed to finish the remainder of the job?

a. 2; b.4; c.5; d.6; e.8

I solve this problem as follows:

15 programmers: 3 days: 1 web
-> 15 programmers: 1 day: 1/3 web
-> 15 programmers: 2 day: 2/3 web
-> 6 programmers: 5 day: 2/3 web

Therefore, 5-2 = 3 days more are needed to finish the remainder of the job

But in the answer key, no choice of 3, and the key is 5

Please show me whether I right, if not, what is my mistake??

Thank you!
When the job is undefined, we can plug in our own value for the job. Plugging in our own value makes work problems much easier. Let's plug in that each programmer does 1 unit/day:

15 programmers = 15*1 = 15 units/day.
Over 3 days, 3*15 = 45 units. So job = 45.
After 1 day, 45-15 = 30 units left.
15-9 = 6 programmers left, so new rate is 6*1 = 6 units/day.
30/6 = 5 days.

The correct answer is C.
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