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Recently, scientists were able to sequence an individual's h [#permalink]
06 Dec 2013, 07:37

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This post was BOOKMARKED

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D

E

Difficulty:

35% (medium)

Question Stats:

68% (02:55) correct
33% (01:46) wrong based on 40 sessions

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?

Re: Recently, scientists were able to sequence an individual's.. [#permalink]
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

Re: Recently, scientists were able to sequence an individual's h [#permalink]
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?

Re: Recently, scientists were able to sequence an individual's h [#permalink]
26 Dec 2013, 21:02

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}

Therefore answer is 4 (D)

gmatclubot

Re: Recently, scientists were able to sequence an individual's h
[#permalink]
26 Dec 2013, 21:02