A quantity increases from 40 to 60. Express this increase as a percentage.
- A. 26%
- B. 50%
- C. 35%
- D. 12%
Correct Answer: B
Rationale: To calculate the percentage increase, use the formula:
Percentage Increase = ((New Value - Original Value) / Original Value) x 100
Substitute the values:
((60 - 40) / 40) x 100 = (20 / 40) x 100 = 0.5 x 100 = 50%
Therefore, the correct answer is 50%.
Choice A (26%) is incorrect as the percentage increase is not 26%. Choice C (35%) is incorrect as the percentage increase is not 35%. Choice D (12%) is incorrect as the percentage increase is not 12%.
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Juan wishes to compare the percentages of time he spends on different tasks during the workday. Which of the following representations is the most appropriate choice for displaying the data?
- A. Line plot
- B. Bar graph
- C. Line graph
- D. Pie chart
Correct Answer: D
Rationale: A pie chart is the most appropriate choice for displaying the percentages of time spent on different tasks during the workday because it visually represents parts of a whole. In this case, each task's percentage represents a part of the entire workday, making a pie chart an ideal way to compare these percentages. Line plots, bar graphs, and line graphs are not suitable for showing percentages of a whole; they are more commonly used for tracking trends, comparing values, or showing relationships between variables but do not efficiently represent parts of a whole like a pie chart does.
You measure the width of your door to be 36 inches. The true width of the door is 75 inches. What is the relative error in your measurement?
- A. 0.52%
- B. 0.01%
- C. 0.99%
- D. 0.10%
Correct Answer: A
Rationale: The relative error is calculated using the formula: (|Measured Value - True Value| / True Value) * 100%. Substituting the values given, we have (|36 - 75| / 75) * 100% = (39 / 75) * 100% ≈ 0.52 * 100% = 0.52%. Therefore, the relative error in measurement is approximately 0.52%. Choice A is correct because it reflects this calculation. Choice B is incorrect as it represents a lower relative error than the actual value obtained. Choice C is incorrect as it overestimates the relative error. Choice D is incorrect as it underestimates the relative error.
What kind of relationship between a predictor and a dependent variable is indicated by a line that travels from the bottom-left of a graph to the upper-right of the graph?
- A. Positive
- B. Negative
- C. Exponential
- D. Logarithmic
Correct Answer: A
Rationale: A line that travels from the bottom-left of a graph to the upper-right of the graph signifies a positive relationship between the predictor and dependent variable. This indicates that as the predictor variable increases, the dependent variable also increases. Choice B, 'Negative,' is incorrect as a negative relationship would be depicted by a line that travels from the top-left to the bottom-right of the graph. Choices C and D, 'Exponential' and 'Logarithmic,' respectively, represent specific types of relationships characterized by non-linear patterns, unlike the linear positive relationship shown in the described scenario.
Kimberley earns $10 an hour babysitting, and after 10 p.m., she earns $12 an hour, with the amount paid being rounded to the nearest hour accordingly. On her last job, she worked from 5:30 p.m. to 11 p.m. In total, how much did Kimberley earn on her last job?
- A. $45
- B. $57
- C. $62
- D. $42
Correct Answer: C
Rationale: Kimberley worked from 5:30 p.m. to 11 p.m., which is a total of 5.5 hours before 10 p.m. (from 5:30 p.m. to 10 p.m.) and 1 hour after 10 p.m. The earnings she made before 10 p.m. at $10 an hour was 5.5 hours * $10 = $55. Her earnings after 10 p.m. for the rounded hour were 1 hour * $12 = $12. Therefore, her total earnings for the last job were $55 + $12 = $67. Since the amount is rounded to the nearest hour, the closest rounded amount is $62. Therefore, Kimberley earned $62 on her last job. Choice A is incorrect as it does not consider the additional earnings after 10 p.m. Choices B and D are incorrect as they do not factor in the hourly rates and the total hours worked accurately.
On a floor plan drawn at a scale of 1:100, the area of a rectangular room is 50 cm². What is the actual area of the room?
- A. 500 m²
- B. 50 m²
- C. 5000 cm²
- D. 500 cm²
Correct Answer: D
Rationale: The scale of 1:100 means that 1 cm² on the floor plan represents 100 cm² in real life. To find the actual area of the room, you need to multiply the area on the floor plan by the square of the scale factor. Since the scale is 1:100, the scale factor is 100. Therefore, 50 cm² on the floor plan represents 50 * 100 = 5000 cm² in real life. Choice A (500 m²) is incorrect as it converts the area from cm² to m² without considering the scale factor. Choice B (50 m²) is incorrect as it does not account for the scale factor. Choice C (5000 cm²) is incorrect as it gives the area on the floor plan, not the actual area.
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