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# Recently, scientists were able to sequence an individual's h

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Intern
Joined: 24 Dec 2012
Posts: 23
Concentration: Entrepreneurship, Social Entrepreneurship
WE: Design (Computer Software)
Recently, scientists were able to sequence an individual's h  [#permalink]

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06 Dec 2013, 07:37
5
00:00

Difficulty:

45% (medium)

Question Stats:

68% (02:39) correct 32% (02:33) wrong based on 158 sessions

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Recently, scientists were able to sequence an individual's humane genome in just 4 weeks using a super fast modern computer. A computer manufactured just 2 years earlier would have taken 24 weeks to do the same amount of work.

For more targeted treatment of his cancer, Steve needs his human genome to be sequenced as soon as possible and scientists plan to use a combination of the same number of "new" computers as "2 year-old" computers to work together. Assuming the computers can tackle discrete components of the genome sequencing process, how many combined sets of computers should the scientists order if they want to finish the genome project in 6 days?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5
Intern
Status: I'm trying to GMAT?
Joined: 12 Feb 2013
Posts: 23
Location: United States
Concentration: Finance, General Management
GMAT Date: 06-22-2013
WE: Engineering (Consulting)
Re: Recently, scientists were able to sequence an individual's..  [#permalink]

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06 Dec 2013, 09:31
For more targeted treatment of his cancer, Steve needs his human genome to be sequenced as
soon as possible and scientists plan to use a combination of the same number of "new" computers
as "2 year-old" computers to work together. Assuming the computers can tackle discrete
components of the genome sequencing process, how many combined sets of computers should
the scientists order if they want to finish the genome project in 6 days?

New rate: 1/4
2 year-old rate: 1/24

Now we are told same number of new and 2 year old computers will be used to sequence 1 genome in 6 days

Work: 1 genome
Time: 6 days or 6/7 weeks
Number of new and 2 year-old computers: Both x

(1/4(x)+1/24(x))*6/7=1
7/24(x)*6/7=1
1/4(x)=1
x=4

We are asked for the combination. Both old and new computers = 4, So 4 combos
SVP
Joined: 06 Sep 2013
Posts: 1744
Concentration: Finance
Re: Recently, scientists were able to sequence an individual's h  [#permalink]

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26 Dec 2013, 05:44
tusharGupta1 wrote:
Recently, scientists were able to sequence an individual's humane genome in just 4 weeks using a super fast modern computer. A computer manufactured just 2 years earlier would have taken 24 weeks to do the same amount of work.

For more targeted treatment of his cancer, Steve needs his human genome to be sequenced as soon as possible and scientists plan to use a combination of the same number of "new" computers as "2 year-old" computers to work together. Assuming the computers can tackle discrete components of the genome sequencing process, how many combined sets of computers should the scientists order if they want to finish the genome project in 6 days?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

x/4 + x/24 = 6/7

x = 144/49

We need four computers

Hope it helps
Cheers!
J
Intern
Joined: 17 Aug 2013
Posts: 1
Re: Recently, scientists were able to sequence an individual's h  [#permalink]

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26 Dec 2013, 21:02
1
Convert weeks to days on rates:

New computer: $$\frac{1}{4}$$ -> $$\frac{1}{28}$$
Old computer: $$\frac{1}{24}$$ -> $$\frac{1}{168}$$

Combine Rates:

$$\frac{1}{28}$$+ $$\frac{1}{168}$$
= $$\frac{1}{24}$$

We need the set of computers to do the job in 6 days, so: if one set takes $$\frac{1}{24}$$, we need to add this rate to itself enough times to get $$\frac{1}{6}$$

4 x $$\frac{1}{24}$$ gives us $$\frac{1}{6}$$

Manager
Joined: 06 Nov 2016
Posts: 61
Location: Viet Nam
GPA: 3.54
Re: Recently, scientists were able to sequence an individual's h  [#permalink]

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25 Aug 2018, 01:34
tusharGupta1 wrote:
Recently, scientists were able to sequence an individual's humane genome in just 4 weeks using a super fast modern computer. A computer manufactured just 2 years earlier would have taken 24 weeks to do the same amount of work.

For more targeted treatment of his cancer, Steve needs his human genome to be sequenced as soon as possible and scientists plan to use a combination of the same number of "new" computers as "2 year-old" computers to work together. Assuming the computers can tackle discrete components of the genome sequencing process, how many combined sets of computers should the scientists order if they want to finish the genome project in 6 days?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

Here is my approach.

______________$$Work=Rate*Time (weeks)$$
1 new computer:___ $$1 = \frac{1}{4} * 4$$

1 old computer: ___ $$1 = \frac{1}{24} * 24$$

(1 set) Total:______ $$1 = (\frac{1}{4} + \frac{1}{24}) * time$$

(x sets) Total: _____ $$1 = x*(\frac{1}{4} + \frac{1}{24})* \frac{6}{7}$$

-> $$1 = x*(\frac{6}{4*7} + \frac{6}{24*7})$$ --> $$x=4$$
_________________
Manager
Joined: 04 Oct 2017
Posts: 67
Recently, scientists were able to sequence an individual's h  [#permalink]

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25 Aug 2018, 17:21
afactor4 wrote:
Convert weeks to days on rates:

New computer: $$\frac{1}{4}$$ -> $$\frac{1}{28}$$
Old computer: $$\frac{1}{24}$$ -> $$\frac{1}{168}$$

Combine Rates:

$$\frac{1}{28}$$+ $$\frac{1}{168}$$
= $$\frac{1}{24}$$

We need the set of computers to do the job in 6 days, so: if one set takes $$\frac{1}{24}$$, we need to add this rate to itself enough times to get $$\frac{1}{6}$$

4 x $$\frac{1}{24}$$ gives us $$\frac{1}{6}$$

Hi,

I have a doubt. Total days taken to complete the job by the two computers is 24. When I solve it as
1set of computers = 24 days
x=6 days
I get x=1/4. Where am I wrong????

When I solve using per day work I get 4 sets.
1 set = 1/24 days
x = 1/6
x= 4 sets
Manager
Joined: 06 Nov 2016
Posts: 61
Location: Viet Nam
GPA: 3.54
Re: Recently, scientists were able to sequence an individual's h  [#permalink]

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25 Aug 2018, 19:46
Kezia9 wrote:
afactor4 wrote:
Convert weeks to days on rates:

New computer: $$\frac{1}{4}$$ -> $$\frac{1}{28}$$
Old computer: $$\frac{1}{24}$$ -> $$\frac{1}{168}$$

Combine Rates:

$$\frac{1}{28}$$+ $$\frac{1}{168}$$
= $$\frac{1}{24}$$

We need the set of computers to do the job in 6 days, so: if one set takes $$\frac{1}{24}$$, we need to add this rate to itself enough times to get $$\frac{1}{6}$$

4 x $$\frac{1}{24}$$ gives us $$\frac{1}{6}$$

Hi,

I have a doubt. Total days taken to complete the job by the two computers is 24. When I solve it as
1set of computers = 24 days
x=6 days
I get x=1/4.
Where am I wrong????

When I solve using per day work I get 4 sets.
1 set = 1/24 days
x = 1/6
x= 4 sets

The more working sets of computers, the shorter the time to complete the job.
1 set of computers = 24 days
x sets of computers = 6 days
--> the time to complete the job decreases 4 times, so the number of sets of computers need to increases 4 times. In other words, x = 4.

Hope it's clear.
_________________
Re: Recently, scientists were able to sequence an individual's h &nbs [#permalink] 25 Aug 2018, 19:46
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