Critical Reasoning

For the first 10 billion years of a sun-like star's lifetime, the temperature in the core increases gradually, resulting in a steadily increasing luminosity. After about 4.5 billion years, an average main sequence star similar to the sun shines one and a half times brighter than it did when it first began emittinglight. Therefore, if a 4.5 billion-year-old main sequence star has a luminosity half that of the sun, its luminosity has increased much slower than the average.

which of the following indicates a flaw in the reasoning above?

A. Luminosity is only one measure of regular stellar evolution
B. The conclusion is based off of an ambiguous interpretation of the term "average"
C. since humans cannot live long enough to observe a star's lifecycle, the "age" of a star cannot be measured.
D. Some stars could have lifetimes shorter than the 4.5 billion year limit
E. Average lumibosity increase is not the same as average luminosity

















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Answer:E

Why option B is wrong here? The term "average" can be ambiguous since it is not clear about what it refers to. "Average" can be either "the average lumninosity" or "the average luminosity increase".

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