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The population of the U.S. grew by 29% between 1979 and 2004, during w
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05 Dec 2022, 04:42
05 Dec 2022, 04:42
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The population of the U.S. grew by 29% between 1979 and 2004, during which time per capita energy consumption doubled. If average per capita energy used from coal was 25 MBTUs in 1979, which of the following are in the range of per capita energy, measured in MBTUs, provided by a single fossil fuel (coal, natural gas or oil) in 2004 ?
Indicate all such values.
12
25
37
41
61
79
Re: The population of the U.S. grew by 29% between 1979 and 2004, during w
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09 Dec 2022, 04:00
09 Dec 2022, 04:00
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OE
Ignore the population growth: The question is asked in per capita terms, so it’s asking about the population as a whole. Coal production was 25 in 1979, when, according to the graph, coal represented 27% of energy; since 25 is 27% of 92.6, the total energy was 92.6 in 1979, and double that, or 185.2, in 2004. The lower end of the range is oil, at about 17%, and 17% of 185.2 is about 31.5; the upper end of the range is coal, at about 34%, or about 63. Choices (C), (D), and (E) fall within the range.
Ignore the population growth: The question is asked in per capita terms, so it’s asking about the population as a whole. Coal production was 25 in 1979, when, according to the graph, coal represented 27% of energy; since 25 is 27% of 92.6, the total energy was 92.6 in 1979, and double that, or 185.2, in 2004. The lower end of the range is oil, at about 17%, and 17% of 185.2 is about 31.5; the upper end of the range is coal, at about 34%, or about 63. Choices (C), (D), and (E) fall within the range.
The population of the U.S. grew by 29% between 1979 and 2004, during w
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18 Mar 2023, 07:39
18 Mar 2023, 07:39
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Expert Reply
The share of each energy source in total consumption is the same as the share of each energy source in per capita consumption.
For example, coal consumption accounts for 0.27 of the total energy consumption, so coal also accounts for 0.27 of the per capita energy consumption. So the total per capita energy consumption in 1979 is 25/0.27=92.59 2004 doubled 185.18
In 2004, coal per capita was 62.96, ng per capita was 61.11, and oil per capita was 31.48.
Finally, ask which number is in the range of these three numbers, CDE.
The 29% population growth in this question is redundant data.
For example, coal consumption accounts for 0.27 of the total energy consumption, so coal also accounts for 0.27 of the per capita energy consumption. So the total per capita energy consumption in 1979 is 25/0.27=92.59 2004 doubled 185.18
In 2004, coal per capita was 62.96, ng per capita was 61.11, and oil per capita was 31.48.
Finally, ask which number is in the range of these three numbers, CDE.
The 29% population growth in this question is redundant data.
