400-1816-180
本題由lindy提供
Technological improvements and reduced equipment costs have made converting solar
Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not decreased 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.
視頻解析
暫無視頻解析，點擊獲取更多視頻內(nèi)容
文字解析
文中
(1) ：太陽能發(fā)電的成本=將太陽能轉化為電能的成本
(2)：火力發(fā)電的成本=石油的成本+將石油轉化為電能的成本 這兩個公式的區(qū)別在于：太陽能是不要錢的，而石油要錢。 而當石油的成本=臨界點(threshold)的時候， (1) = (2) 即：太陽能轉化成電能的成本= threshold+將石油轉化成電能的成本 由此得到：(3) threshold= 太陽能轉化成電能的成本 - 將石油轉化成電能的成本 所以，threshold只是兩種發(fā)電成本的差，是由兩種發(fā)電的成本決定的，與實際的油價并沒有關系。所以，A選項是無關選項。 而題目中提到說，太陽能轉化的效率提高（即成本下降），而threshold不變，那么從公式(3)中就很容易得到：是因為石油轉化成電能的成本也降低了（即火力發(fā)電效率提高）。 所以選C。
GMAT會員
- 【OG18-P680-668題】In a review of 2,000 studies of human behavior that date back to the 1940s, two Swiss psychologists, declaring that since most of the studies had failed to control for such variables as social class and family size, none could be taken seriously.
- 【OG18-P680-671題】Manufacturers rate batteries in watt-hours; if they rate the watt-hour higher, the longer the battery can be expected to last.
- 【OG18-P680-672題】At the end of the 1930s, Duke Ellington was looking for a composer to assist him-someone not only who could arrange music for his successful big band, but mirroring his eccentric writing style as well in order to finish the many pieces he had started but never completed.
- 【OG20-P569-634題】Snowmaking machines work by spraying a mist that freezes immediately on contact with cold air. Because the sudden freezing kills bacteria, QuickFreeze is planning to market a wastewater purification system that works on the same principle. The process works only when temperatures are cold, however, so municipalities using it will still need to maintain a conventional system. Which of the following, if true, provides the strongest grounds for a prediction that municipalities will buy QuickFreeze's purification system despite the need to maintain a conventional purification system as well?
- 【OG20-P147-8題】(12 -13 )+(13 -14 )+(14 -15 )+(15 -16 )=
添加官方小助手微信
了解更多GMAT考試與咨詢
12G備考資料