In 1994, Airline A bought 25 airplanes. All of these airplanes either remained in Airline A’s inventory or were sold to another airline. What percent of these airplanes were sold to another airline?
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Solution
Looking at the 2002 inventory at Airline A, 4% was purchased in 1994.The actual number in inventory is 4% of 250, or 10 airplanes. Of the 25 airplanes purchased, 15 must have been sold. Use percent translation to translate the question into algebra: “15 is what percent of 25” becomes 15= \(\frac{x}{100}\) × 25. Solving for x gives you 60, choice (D).
What was the total number of inventoried airplanes purchased by both airlines from 1997 to 1999?
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Solution
From 1997 to 1999, Airline A bought 44% of its 250 airplanes, or 110 airplanes. In the same time period, Airline B bought 26% of its 450 airplanes, or 117 airplanes.The sum of 110 and 117 is 227 airplanes, choice (D).
By approximately what percentage did the number of colonies in Region Z decrease from the year with the highest number to that with the lowest number?
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Solution
Use the graph to estimate your starting values and then use the percent change formula, which is \(\frac{difference}{original}\) × 100.The largest number of colonies—about 12,000—was in 1981, while 1984 and 1986 appear to be tied for lowest at about 5,000 colonies. Since all values are in the thousands, simplify by calling your values 12 and 5:\(\frac{12-5}{12}\times 100=\frac{7}{12}\times 100\), which is approximately 60%. As always, watch out for trap answers: If you selected choice (A), you may have set the original value to 5 instead of 12.
What was the approximate value, in dollars, of the honey produced in Region Z in 1985?
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Solution
Since the problem asks for the approximate value of Region Z’s honey production in 1985, you’ll need to use the first and third graphs.The first graph tells you that there were about 15,000 pounds of honey produced that year, and the third graph tells you that each pound was worth just less than 125 cents, so try 120 cents—or, since the answer needs to be in dollars, $1.20: 15,000 pounds × $1.20 per pound = $18,000.The closest answer is choice (A).
From 1996 to 1998, the value of golf equipment and supplies produced by SouthKorea increased by approximately what percent?
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Solution
For this problem, be sure to get the correct dollar values from the chart and to use the percent change formula:\(\frac{difference}{original}\) × 100. Because the increase was from $384 million in 1996 to $457 million in 1998, the difference is $73 million;\(\frac{73}{384}\) × 100 reduces to 19.01%.The answer is choice (D). If you got choice (C), you may have mistakenly used the ending value, $457 million, in place of the original value.
In 1994, the total production for golf equipment and supplies from which country was nearest in value to the combined production of balls, bags, and gift items in the United States in the same year?
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Solution
Start by adding the appropriate percentages from the pie chart for 1994: 16% (balls) + 7% (bags) + 3% (gift items) = 26%. Next, find the percentage for the United States total for that year: 26% of $2,691 million is $699.66 million. Finally, find the value in the chart that is nearest $699.66 million—Japan, at $678 million, is the closest.
In 1994, the value of clubs produced in the United States was approximately what percent of the value of golf equipment and supplies produced in the world?
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Solution
Avoid the temptation to work this problem in dollars—you can save considerable effort by dealing directly with the percentages.The pie chart for 1994 shows that clubs made up 25% of the total U.S. production, and the table shows that the United States accounted for 62.3% of the total world production; 25% (or 1⁄4) of 62.3% is 15.575%, which is closest to choice (C), 16%.
Which of the following can be inferred from the graphs?
Indicate all possible values.
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Solution
B and C
B,C Choice (A) is incorrect; the graph gives no information on the number of power plants constructed.Choice (B) is correct. In 1979, coal and oil were each 26% and natural gas was 34% of total energy used, for a total of 68%. In 2004, coal was 34%, natural gas was 33%, and oil was 18% of total energy used, for a total of 85%. For choice (C), the amount of energy used from hydroelectric sources in 1979 is approximately 925 units and the amount for 2004 is approximately 203 units.You calculate these figures by using the different totals for each year and the percentage of total energy represented on the graph by hydroelectric energy. 203 is less than one fourth of 925, and thus choice (C) is valid.
What is the approximate ratio of energy used from oil in 1979 to energy used from oil in 2004 ?
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Solution
For 1979, find 27.5% of 18,509, which is approximately 5,090. For 2004, find 17.5% of 20,623, which is approximately 3,609. Round the numbers and reduce the ratio:\(\frac{5000}{3600}=\frac{25}{18}\), choice (D).
The “monthly midpoint” is calculated by taking the average (arithmetic mean) of a month’s average high and low. Which of the following is the average monthly midpoint in City X for the 3-month period from July to September?
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Solution
This is a multi-step problem, so you should take it one step at a time. First, determine the monthly midpoint for each month.The high in July is 78, and the low is 59, so the monthly midpoint is: 78 + 59 = 137 ÷ 2 = 68.5. Similarly, the midpoint for August is: 76 + 57 = 133 ÷ 2 = 66.5. September’s midpoint is: 68 + 50 = 118 ÷2 = 59.The average of the three midpoints is: 59 + 66.5 + 68.5 = 194 ÷ 3 = 64.7, choice (C).