Critical Reasoning

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
I nailed this one, still the options seemed a bit close, would love to see other views on this.

All we need to know is that output per miner is double what it was 5 years ago due to technology.

A. Correct. If output per miner has doubled in the last 5 years and the number of miners in the country is constant then output would have doubled in the country.

B. Incorrect. Not necessarily true. Dont confuse overall output with the output per miner. Not all mines have necessarily used the new technology. Its possible that new technology triples output which makes up for the fact that some mines did not implement it and remained at constant output per worker. The coal mines output would be increased by just adding new workers not by making them more efficient.

C. Incorrect. This makes the assumption that a new mine would have used the new technology, which is not necessarily true.

D. Incorrect. Again they are trying to trick you by interchanging overall output and output per worker. There is nothing that says a mine cant have simply hired new workers rather than using technology. Output per worker could remain constant or have decreased but overall production would go up.

E. Incorrect. The cost of coal has nothing to do with output