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What is a direct proportion? What is an inverse proportion?
- A. Direct: Both quantities increase or decrease together; Inverse: When one quantity increases, the other decreases by the same factor
- B. Direct: Both quantities decrease together; Inverse: When one quantity increases, the other increases
- C. Direct: One quantity stays the same while the other increases; Inverse: Both quantities increase together
- D. Direct: One quantity increases while the other decreases; Inverse: Both quantities decrease together
Correct Answer: A
Rationale: In a direct proportion, both quantities increase or decrease together. This means that as one quantity goes up, the other also goes up, and vice versa. On the other hand, in an inverse proportion, when one quantity increases, the other decreases by the same factor. Therefore, choice A is correct as it accurately defines direct and inverse proportions. Choices B, C, and D are incorrect because they do not accurately describe the relationship between quantities in direct and inverse proportions.
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Histograms use ________, and bar graphs do not.
- A. Ranges
- B. Categories
- C. Labels
- D. Percentages
Correct Answer: A
Rationale: Correct Answer: Ranges. Histograms utilize ranges (intervals) to display the frequency distribution of continuous data, highlighting the frequency of values falling within each interval. Bar graphs, on the other hand, represent discrete data using separate and distinct bars to show comparisons between different categories or groups. Choice B (Categories) is incorrect because both histograms and bar graphs can display data based on categories, but histograms use ranges to group continuous data. Choice C (Labels) is incorrect as both types of graphs can have labels to provide context and information. Choice D (Percentages) is incorrect because percentages can be used in both histograms and bar graphs to show proportions, but they are not a defining feature that distinguishes histograms from bar graphs.
Erma has her eye on two sweaters, one for $50 and one for $44. With a sale of 25% off the cheaper item, what will she spend?
- A. 79
- B. 81
- C. 83
- D. 85
Correct Answer: A
Rationale: Erma pays full price for the $50 sweater and gets 25% off the $44 sweater. 25% of $44 is $11, so she pays $33 for the second sweater. Therefore, the total amount Erma spends is $50 (first sweater) + $33 (second sweater) = $79. Choices B, C, and D are incorrect as they do not correctly calculate the total amount Erma would spend on both sweaters.
Complete the following equation: 5 + 3 4 - 6 / 2 = ?
- A. 5
- B. 9
- C. 11
- D. 7
Correct Answer: B
Rationale: To solve this equation, follow the order of operations (PEMDAS/BODMAS): First, perform multiplication and division from left to right. 3 4 equals 12, and 6 / 2 equals 3. Then, carry out addition and subtraction from left to right. 5 + 12 - 3 equals 14, not 9. Therefore, the correct answer is 14, making choice B the correct answer. Choices A, C, and D can be eliminated as they do not match the correct result obtained by following the order of operations.
When is a histogram preferred over a bar graph?
- A. Comparison between categories
- B. Frequency
- C. Percentages
- D. Proportions
Correct Answer: B
Rationale: Histograms are specifically designed to display the frequency distribution of continuous data, showing the distribution of values over intervals or bins. On the other hand, bar graphs are used to compare different categories or discrete data points. Therefore, the correct answer is B. Choices A, C, and D are incorrect because histograms are not primarily used for comparing categories, percentages, or proportions, but rather for visualizing the distribution of frequencies within data intervals.
What is the probability of consecutively pulling two more orange blocks, without replacement, from a bag containing 3 orange blocks, 5 green blocks, and 4 purple blocks?
- A. 3/12
- B. 3/55
- C. 2/10
- D. 1/3
Correct Answer: B
Rationale: To calculate the probability of consecutively pulling two more orange blocks without replacement, we first determine the probability of pulling an orange block on the first draw, which is 3/12 (3 orange blocks out of 12 total blocks). After removing one orange block, there are only 11 blocks left, so the probability of pulling another orange block on the second draw is 2/11. To find the combined probability, we multiply the probabilities together: (3/12) * (2/11) = 6/132 = 3/55. Therefore, the correct answer is B. Choice A (3/12) incorrectly simplifies the probability before calculating the second draw. Choice C (2/10) does not consider the specific number of orange blocks in the bag. Choice D (1/3) does not account for the reduced number of blocks after the first draw.