On this book, I only have one question.
This area is one of the most tricky!!
For P. 150 - Problem C.
I don't understand the solution for the third statement.
Thanks.
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Re: #6 - Comp Guide P. 150 - Problem C
Let's dive right into this one--it's incredibly complex and highly technical, and I strongly recommend you spend a good half hour reading over the solution on page 155.
Guide 6, Page 149-150, Problem C
See study guide for graphs.
Problem 1
Approximately what percent of the mining industries' average annual production in 1991-1995 came from the production of aluminum?
A) 4%
B) 7%
C) 11%
D) 22%
E) It cannot be determined from the information given.
The correct answer is E. This is one of those rare GRE problems where you actually don't have enough information to solve the problem--the question is asking about aluminum specifically, but you are only given information about aluminum, uranium, and titanium as one single quantity. Knowing what is going on with an aggregate does not mean you know what's going on with each part, so there simply is not enough information to find an answer.
Problem 2
Approximately what percent of average annual GDP of Province P from 1996-2000 came from copper production?
A) 3%
B) 6%
C) 9%
D) 14%
E) 16%
This problem asks for an approximate answer, so don't be afraid to start approximating right off the bat. We know that copper mining represents only a part of metal mining, so there's no way that it can be over 9%, the total amount derived from mining metals. That eliminates D and E right off the bat. Looking down at the table, we see that copper mining represents about one-third of the total metal mining (the 3 right columns). 1/3(9%) = 3%, which is the correct answer.
To be thorough, you could argue that copper mining represents only a part of metal mining, and if we look on the table for 1996-2000, we see it represents 16% of the total amount of mining income. Looking at the chart, we see that the total GDP derived from mining was about 9% (metals) + 3% (salt) + 3% (coal) + 3% (borates) = 18%. 16% of 18% is about 3%. The correct answer is A.
Problem 3
Which of the following can be inferred from the information given? Choose all that apply.
A) For all the time periods shown, borate production, in millions of 2005 dollars, was the same.
B) Of the time periods shown, 1981-1985 was the one in which the mining industries produced the greatest value of gold and silver, measured in 2005 dollars.
C) Of the time periods shown, 2001-2005 had the highest average annual GDP, measured in 2005 dollars.
None of these problems are particularly hard, we just have to be really, really careful that we look at the correct quantities, and that's what makes this a problem that 90+% of GRE test-takers will get wrong.
A is obviously untrue. The percentage of Mining Industries' production of borate was 15% for each year, but the dollar amount for each year fluctuated--the dollar value of borate was 15% of the value in the first column of the table for each 5 year period.
B is true. You can compute the value of gold and silver for each 5 year period on your calculator, but it'll be faster if you notice that if you multiply a larger number by a larger percent, you'll get a larger result. In 1981-85, the dollar value was $342.5 (the highest) and the percentage attributable to gold and silver alone was 20%. 1986-90 and 1991-95 both had smaller dollar values and smaller percentages, so we can ignore them. 1996-2000 and 2001-05 had smaller dollar values but larger percentages, so we should check them.
1981-85: 20% of 342.5 = 68.5
1996-2000: 22% of 257.9 = 56.738
2001-05: 24% of 205.0 = 49.2
1981-85 is clearly the largest, so B is true.
C is false. To determine the whole GDP, we need a fraction of the GDP that we know, along with a dollar value for the GDP that we know. Let's use the entire mining industry, where we have the dollar value for the entire industry given to us in the table, and which represents the coal, salt, metals, and borates columns on the graph. The years with the highest dollar value of production from Mining Industries (1981-85, with $342.5 million) correspond to the years when mining accounted for the smallest fraction of GDP (about 12% total). This means that the GDP must have been significantly larger in 1981-85 than it is in 2001-2005, when $205 million of mining represented about one-quarter of Province P's total GDP. 2001-05, in fact, represented the lowest GDP for Province P.
Guide 6, Page 149-150, Problem C
See study guide for graphs.
Problem 1
Approximately what percent of the mining industries' average annual production in 1991-1995 came from the production of aluminum?
A) 4%
B) 7%
C) 11%
D) 22%
E) It cannot be determined from the information given.
The correct answer is E. This is one of those rare GRE problems where you actually don't have enough information to solve the problem--the question is asking about aluminum specifically, but you are only given information about aluminum, uranium, and titanium as one single quantity. Knowing what is going on with an aggregate does not mean you know what's going on with each part, so there simply is not enough information to find an answer.
Problem 2
Approximately what percent of average annual GDP of Province P from 1996-2000 came from copper production?
A) 3%
B) 6%
C) 9%
D) 14%
E) 16%
This problem asks for an approximate answer, so don't be afraid to start approximating right off the bat. We know that copper mining represents only a part of metal mining, so there's no way that it can be over 9%, the total amount derived from mining metals. That eliminates D and E right off the bat. Looking down at the table, we see that copper mining represents about one-third of the total metal mining (the 3 right columns). 1/3(9%) = 3%, which is the correct answer.
To be thorough, you could argue that copper mining represents only a part of metal mining, and if we look on the table for 1996-2000, we see it represents 16% of the total amount of mining income. Looking at the chart, we see that the total GDP derived from mining was about 9% (metals) + 3% (salt) + 3% (coal) + 3% (borates) = 18%. 16% of 18% is about 3%. The correct answer is A.
Problem 3
Which of the following can be inferred from the information given? Choose all that apply.
A) For all the time periods shown, borate production, in millions of 2005 dollars, was the same.
B) Of the time periods shown, 1981-1985 was the one in which the mining industries produced the greatest value of gold and silver, measured in 2005 dollars.
C) Of the time periods shown, 2001-2005 had the highest average annual GDP, measured in 2005 dollars.
None of these problems are particularly hard, we just have to be really, really careful that we look at the correct quantities, and that's what makes this a problem that 90+% of GRE test-takers will get wrong.
A is obviously untrue. The percentage of Mining Industries' production of borate was 15% for each year, but the dollar amount for each year fluctuated--the dollar value of borate was 15% of the value in the first column of the table for each 5 year period.
B is true. You can compute the value of gold and silver for each 5 year period on your calculator, but it'll be faster if you notice that if you multiply a larger number by a larger percent, you'll get a larger result. In 1981-85, the dollar value was $342.5 (the highest) and the percentage attributable to gold and silver alone was 20%. 1986-90 and 1991-95 both had smaller dollar values and smaller percentages, so we can ignore them. 1996-2000 and 2001-05 had smaller dollar values but larger percentages, so we should check them.
1981-85: 20% of 342.5 = 68.5
1996-2000: 22% of 257.9 = 56.738
2001-05: 24% of 205.0 = 49.2
1981-85 is clearly the largest, so B is true.
C is false. To determine the whole GDP, we need a fraction of the GDP that we know, along with a dollar value for the GDP that we know. Let's use the entire mining industry, where we have the dollar value for the entire industry given to us in the table, and which represents the coal, salt, metals, and borates columns on the graph. The years with the highest dollar value of production from Mining Industries (1981-85, with $342.5 million) correspond to the years when mining accounted for the smallest fraction of GDP (about 12% total). This means that the GDP must have been significantly larger in 1981-85 than it is in 2001-2005, when $205 million of mining represented about one-quarter of Province P's total GDP. 2001-05, in fact, represented the lowest GDP for Province P.
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