prameko wrote:I 'm not understand the explaination answer. plz help and explain in the easier way.

1. 15 Java 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) 5.
(b) 2.
(c) 8.
(d) 4.
(e) 6.

Hi Prameko,

There are many ways to approach this question, but in my opinion, the following is a universal approach in that it can be expanded to accomodate any subtlety that GMAT test-makers impose on us. So, in reality it works in every proportionailty problem AND more importantly we understand what we are doing.

The assumption of every such question is that all people work exactly at the same rate (unless otherwise specified)

15 Programmers------------ 1 job -------------------- 3 days.
Therefore,
1 programmer----------------1 job ------------------- (15) (3) = 45 days.

Also,
15 programmers ------------1/3rd job -----------------1 day.

{ ^^This is a very important step in the problem, coz now you can answer any question that can be posed, since you have converted everything into rates based on 1 day or 1 person}

{The Condition: 9 programmers leave after 1 day. But, the 15 programmers finished 1 day's work together. This is 1/3rd of the work. This leaves 2/3rds of the work to be finished.}

There are only 6 programmers left to finish the webpage. What is the rate of work of 6 programmers on this kind of a job?

1 programmer-----------------1 job------------------------ 45 days.
Therefore,
6 programmers--------------- 1 job----------------------- 45/6 days (since work gets shared and gets done faster).

But we need only 2/3rd of the work to get done.

6 programmers---------------1 job---------------------45/6 days
6 programmers--------------2/3rd job----------------- ??????

Multiply 45/6 with 2/3rds to get the answer as 5 days more .qa = A.

The last step is a standard proportionality set-up. If you need any help with that, please let me know.

Thank You Musiq for your easier explaination.
I'm understand it better now . I always have problem about this kind of work problems. I take so long time to solve it.

Actually, I just had GMAT test last week and I was so upset about it. I could not finish it on time (many questions left) both math and verbal. I plan to retake next month. Can I have ur suggestion to improve about 100? Moreover, I may have many GMAT to ask you later.

prameko wrote: Actually, I just had GMAT test last week and I was so upset about it. I could not finish it on time (many questions left) both math and verbal. I plan to retake next month. Can I have ur suggestion to improve about 100? Moreover, I may have many GMAT to ask you later.

Please feel free to ask any questions. As far as my knowledge extends, I will help you.

Good luck when you retake the exam. Dont be upset that you have to retake the exam.

GMAC has research that shows 23% of all test-takers repeat the exam. Thats 1 in 4 people.

My point is that its not you, its probably the GMAT itself. Luckily we know that the GMAT has a set testing phiolosophy. Try to capture that in your preparation.

That will really help. And of course, please finish the test. Thats really important. Unfinished tests result in huge score losses.

Can u explain another one.

2. Two carpenters, working in the same pace, can build 2 desks in two hours and a half. How many desks can 4 carpenters build in 4 hours?

(a) 2.4.
(b) 3.6.
(c) 4.2.
(d) 5.5.
(e) 6.4

The best answer is E.
2 carpenters build 2 desks in 2.5 hours ---> 4 carpenters build 4 desks in 2.5 hours ----> In 4 hours there are (4/2.5 = 1.6) time units. And (4 x 1.6) is 6.4 desks.

prameko wrote:Can u explain another one.

2. Two carpenters, working in the same pace, can build 2 desks in two hours and a half. How many desks can 4 carpenters build in 4 hours?

(a) 2.4.
(b) 3.6.
(c) 4.2.
(d) 5.5.
(e) 6.4

The best answer is E.
2 carpenters build 2 desks in 2.5 hours ---> 4 carpenters build 4 desks in 2.5 hours ----> In 4 hours there are (4/2.5 = 1.6) time units. And (4 x 1.6) is 6.4 desks.

Hi Prameko,

Welcome to BTG. Please do start a new question on a new thread. This will help everyone keep track of the question better.

Regards

@Musiq.. nice explanations btw

thanks, musiq. your explanation is very clear

15 Java 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) 5
(b) 2
(c) 8
(d) 4
(e) 6

We know that the daily rate of 15 workers is 1/3 of the job. To find the daily rate of 6 workers, then, we can set up the following proportion:

15/(1/3) = 6/x

45 = 6/x

45x = 6

x = 6/45 = 2/15 (This is the daily rate of 6 workers.)

Since after 1 day of work 1/3 of the job is completed, the 6 workers now have to complete the remaining 2/3 of the job at the rate of 2/15 of the job per day.

We use the formula work = rate x time. We let x = the time it will take the 6 workers to finish 2/3 of the job.

2/3 = (2/15)(x)

30/6 = x

x = 5

Answer: A