Photovoltaic power plants produce electricity from sunlight. As a result of astonishing recent technological advances...

Victoria April 23, 2019

Hi @Maybeillgetlucky,

The conclusion to this argument is that photovoltaic (PV) power plants offer a less expensive approach to meeting the demand for electricity than traditional power plants. The evidence presented to support this conclusion is that the cost of producing electric power at PV plants is 1/10 of what it was 20 years ago, whereas the traditional plants' costs have increased. However, we don't know the past or current costs of producing electric power at either type of plant.

In order to logically draw the conclusion that PV power plants are a cheaper choice to produce electric power than traditional power plants, 1/10 of the cost for PV power plants 20 years ago must be less than traditional plants cost today.

From this, we can deduce that D is the correct answer. If the cost of producing electric power at PV power plants 20 years ago was 10+ times more than traditional plants, then 1/10 of their cost from 20 years ago would still be the same as or more expensive than traditional power plants. However, if producing electric power at PV plants cost less than 10 times the cost of producing power at a traditional power plant 20 years ago, then 1/10 of their original cost would be cheaper than producing power at a traditional plant based on the prices of 20 years ago and the question tells us that prices have since increased. Therefore, we can be certain that 1/10 of the original cost of PV plants would be more than the cost of traditional power plants.

It is also assumed by the question that PV power plants will be able to meet the demand, however, this is not the overall conclusion of the argument.

Hope this was helpful! Let us know if you have any more questions.