Nokea
What is the equation that describes the relationship between x and y in the table below: x = 2, y = 6; x = 3, y = 9; x = 4, y = 12?
- A. y = 3x
- B. x = 3y
- C. y = x/3
- D. y = x + 3
Correct Answer: A
Rationale: The correct answer is y = 3x. By examining the table provided, we can see that for each increase of 1 in x, y increases by 3. This consistent pattern indicates that y is three times the value of x, leading to the equation y = 3x. Choices B, C, and D do not match the pattern observed in the table and are therefore incorrect.
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What is the formula for the area of a circle?
- A. A = πr²
- B. A = 2πr
- C. A = πd
- D. A = 2πd
Correct Answer: A
Rationale: The correct formula for the area of a circle is A = πr², where π is a mathematical constant approximately equal to 3.14159 and r is the radius of the circle. Choice B, A = 2πr, represents the circumference of a circle, not the area. Choice C, A = πd, incorrectly uses the diameter (d) instead of the radius in the formula for area. Choice D, A = 2πd, is also related to the circumference of the circle, not the area. Therefore, option A is the only correct formula for calculating the area of a circle.
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.
Which of the following best describes the relationship in this set of data?
- A. High positive correlation
- B. Low positive correlation
- C. Low negative correlation
- D. No correlation
Correct Answer: B
Rationale: The correct answer is 'B: Low positive correlation.' In a low positive correlation, the variables tend to increase together, but the relationship is not strong. This description fits the data set provided. Choice A, 'High positive correlation,' is incorrect because the correlation is not strong. Choice C, 'Low negative correlation,' is incorrect as the variables are not decreasing together. Choice D, 'No correlation,' is incorrect because there is a relationship between the variables, albeit weak.
If 9.5% of a town's population of 51,623 people voted for a proposition, approximately how many people voted for the proposition?
- A. 3000
- B. 5000
- C. 7000
- D. 10000
Correct Answer: B
Rationale: To find the approximate number of people who voted for the proposition, multiply the town's population by the percentage that voted: 51,623 * 9.5% = 51,623 * 0.095 ≈ 4,904. Therefore, approximately 5,000 people voted for the proposition. Choice A (3000), C (7000), and D (10000) are incorrect because they do not accurately represent 9.5% of the town's population.
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.