Conclusion! Tribnia's coal Industry.

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amysky_0205: Master | Next Rank: 500 Posts; Posts: 193; Joined: Wed Dec 05, 2012 6:53 amFollowed by: 5 members; Thanked: 4 times

by amysky_0205 » Thu Dec 20, 2012 5:07 am

That the application of new technology can increase the productivity of existing coal mines is demonstrated by the case of Tribnia's coal industry. Coal output per miner in Tribnia is double what it was five years ago, even though no new mines have opened.

Which of the following can be properly concluded from the statement about coal output per miner in the passage?

A.If the number of miners working in Tribnian coal mines has remained constant in the past five years, Tribnia's total coal production has doubled in that period of time.

B.Any individual Tribnian coal mine that achieved an increase in overall output in the past five years has also experienced an increase in output per miner.

C.If any new coal mines had opened in Tribnia in the past five years, then the increase in output per miner would have been even greater than it actually was.

D.If any individual Tribnian coal mine has not increased its output per miner in the past five years, then that mine's overall output has declined or remained constant.

E.In Tribnia the cost of producing a given quantity of coal has declined over the past five years.

OA: A

can someone explain why B is wrong? tks a LOT (:

Source: Beat The GMAT — Critical Reasoning | Thu Dec 20, 2012 5:07 am

The Iceman: Master | Next Rank: 500 Posts; Posts: 194; Joined: Mon Oct 15, 2012 7:14 pmFollowed by: 6 members; Location: India; Thanked: 47 times

by The Iceman » Thu Dec 20, 2012 5:25 am

amysky_0205 wrote:That the application of new technology can increase the productivity of existing coal mines is demonstrated by the case of Tribnia's coal industry. Coal output per miner in Tribnia is double what it was five years ago, even though no new mines have opened.

Which of the following can be properly concluded from the statement about coal output per miner in the passage?

A.If the number of miners working in Tribnian coal mines has remained constant in the past five years, Tribnia's total coal production has doubled in that period of time.

B.Any individual Tribnian coal mine that achieved an increase in overall output in the past five years has also experienced an increase in output per miner.

C.If any new coal mines had opened in Tribnia in the past five years, then the increase in output per miner would have been even greater than it actually was.

D.If any individual Tribnian coal mine has not increased its output per miner in the past five years, then that mine's overall output has declined or remained constant.

E.In Tribnia the cost of producing a given quantity of coal has declined over the past five years.

OA: A

can someone explain why B is wrong? tks a LOT (:

B is incorrect because an increase in overall output inany particular mine can happen even with same number of miners or even lesser number of miners and even vice versa is true.

The only thing we know that if we sum total the output of all the coal mines operating in Tribnian, the figure per miner should have doubled in the past five years

Kasia@EconomistGMAT: GMAT Instructor; Posts: 646; Joined: Mon May 21, 2012 7:08 amFollowed by: 143 members; Thanked: 322 times

by Kasia@EconomistGMAT » Thu Dec 20, 2012 5:37 am

Let's analyze the premises. We learn from the argument that coal output per miner in all Tribnia has doubled in the last five years. However, we don't know anything about particular mines. We also know that no new mines have opened.

Answer B is not a correct conclusion because some mines might have achieved the increase in coal output because they hired new staff. Some others might have used new technology. The fact that the mine achieved an increase in overall output does not prove that there has been an increase in output per miner in this particular mine. If they hired more people, output per miner might have decreased.

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viveksingh222: Senior | Next Rank: 100 Posts; Posts: 39; Joined: Tue Nov 06, 2012 4:15 am; Thanked: 1 times

by viveksingh222 » Sat Dec 22, 2012 4:33 am

amysky_0205 wrote:That the application of new technology can increase the productivity of existing coal mines is demonstrated by the case of Tribnia's coal industry. Coal output per miner in Tribnia is double what it was five years ago, even though no new mines have opened.

Which of the following can be properly concluded from the statement about coal output per miner in the passage?

A.If the number of miners working in Tribnian coal mines has remained constant in the past five years, Tribnia's total coal production has doubled in that period of time.

B.Any individual Tribnian coal mine that achieved an increase in overall output in the past five years has also experienced an increase in output per miner.

C.If any new coal mines had opened in Tribnia in the past five years, then the increase in output per miner would have been even greater than it actually was.

D.If any individual Tribnian coal mine has not increased its output per miner in the past five years, then that mine's overall output has declined or remained constant.

E.In Tribnia the cost of producing a given quantity of coal has declined over the past five years.

OA: A

can someone explain why B is wrong? tks a LOT (:

IMO A

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