GMAT笔试题 - 逻辑问题

genre_wu

GMAT OCT. / Y94
Hotco oil burners, designed to be used in asphalt plants, are so efficient that Hotco will sell one to the Clifton Asphalt plant for no payment other than the cost saving between the total amount the asphalt plant actually paid for oil using its former burner during the last two years and the toal amount it will pay for oil using the Hotco burner during the next two years. On installation, the plant will make an estimated payment, which will be adjusted after two years to equal the actual cost savings.
Which of the following, if it occurred, would constitute a disadvantage for Hotco of the plan described above?
A) Another manufacturer’s introduction to the market of a similarly efficient burner
B) The Clifton Asphalt plant’s need for more than one new burner
C) Very poor efficiency in the Clifton Asphalt plant’s old burner
D) A decrease in the demand for asphalt
E) A steady increase in the price of oil beginning soon after the new burner is installed.
Query: what’s the meaning of the paragraph above?

GMAT 2
14. Technological improvements and reduced equipment costs have made converting solar energy directly into electrictity far more cost-efficient in the last decade. However , the threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants ) is unchanged at thirty-five dollars.
Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not descreasd its threshold of economic viability?
A) The cost of oil has fallen dramatically.
B) The reduction in the cost of solar-power equipment has occurred despite increased raw material costs for that equipment.
C) Technological changes have increased the efficiency of oil-fired power plants.
D) Most electricity is generated by coal-fired or nuclear, rather than oil-fired, power plants.
E) When the price of oil increases, reserves of oil not previously worth exploiting become economically viable.
Query: what’s the meaning of the paragraph above?

genre_wu

Thanks again for your answer... :-)

justag

GMAT OCT. / Y94
ans: E
A manufacturer sells a machine to a plant and the machine can help the plant to save money on oil consumption. The price of the machine is calculated by the plants's savings in oil consumption (actual cost of oil in the last two years, say 1999, 2000-actual cost of oil in the following two years, say 2001, 2002).

The actual cost in the last two years is history data now, and thus it doesn't change. So the lower the new cost, the more the plant will pay for the machine. If the price of oil increases for the following two years, the cost will also increase and the plant will save less and pay less for the machine. Accordingly,that's is disadvantaged to the manufacturer.

GMAT 2
ans: A
the key sentence in the passage is
"the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants "

understand it in this way:
"oil would have to rise to the price (cost of solar engergy converted into one barrel of electricity) in order for new solar power plants to be more economical than new oil-fired power plants "

Solar energy will only be viable when the the ration A is lower than the threshold. Ratio A = (oil unit price) / (production cost of one barrel of electricity by solar energy). Technological improvement decrease the solar cost yet ratio A still mainteins. Why? oil unit cost also decreases