What is the difference between two negative numbers?

Correct Answer: B

Rationale: The correct answer is B: 'Positive number.' When you subtract one negative number from another negative number, the result can be a positive number. For example, the difference between -5 and -3 is 2, which is a positive number. Choice A, 'Negative number,' is incorrect because the result of subtracting two negative numbers can be positive. Choice C, 'Zero,' is incorrect because the difference between two negative numbers is not always zero. Choice D, 'Not enough information,' is incorrect because there is enough information to determine that the difference between two negative numbers can be a positive number.

Correct Answer: B

Rationale: The area of a circle is given by the formula A = π r², where r is the radius. Since only half of the garden needs weeding, we calculate half the area. Using the given value of π (3.14) and a radius of 11.5 feet: A = 0.5 3.14 (11.5)² A = 0.5 3.14 132.25 A = 0.5 415.27 A = 207.64 square feet. Thus, the area that needs weeding is approximately 207.64 square feet, making option B the correct answer. Choice A (207.64) is incorrect as it represents the total area of the circular garden, not just half of it. Choice C (519.08) and Choice D (726.73) are also incorrect as they do not reflect the correct calculation for finding the area of half the circular garden.

Correct Answer: B

Rationale: From Equation 1: 2x + y = 0. Solve for y: y = -2x. Substitute y = -2x into Equation 2: x - 2(-2x) = 8. Simplify to x + 4x = 8, then 5x = 8, and x = 8 · 5 = 1.6. Substitute x = 1.6 back into y = -2x to find y = -3.2. Therefore, one solution is (1.6, -3.2). To find the second solution, use -1.6 for x to get (-1.6, 3.2). Thus, the correct answer is B, representing the solutions (1.8, -3.6) and (-1.8, 3.6). Choices A, C, and D contain incorrect values that do not match the solutions derived from solving the system of equations.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: The difference between two numbers is found by subtracting one from the other. When two numbers are equal, subtracting them results in 0, because any number minus itself is always 0. Therefore, the difference between two equal numbers is always zero, making option C the correct answer. Option A ('Negative') and option B ('Positive') are incorrect as they do not represent the result of subtracting two equal numbers, which always yields zero. Option D ('Not enough information') is also incorrect as the difference between two equal numbers is definitively known to be zero.

Correct Answer: B

Rationale: The correct answer is B: 'Positive number.' When you subtract one negative number from another negative number, the result can be a positive number. For example, the difference between -5 and -3 is 2, which is a positive number. Choice A, 'Negative number,' is incorrect because the result of subtracting two negative numbers can be positive. Choice C, 'Zero,' is incorrect because the difference between two negative numbers is not always zero. Choice D, 'Not enough information,' is incorrect because there is enough information to determine that the difference between two negative numbers can be a positive number.

Correct Answer: A

Rationale: To convert liters to kiloliters, divide by 1000 since there are 1000 liters in a kiloliter. Therefore, 147 liters = 0.147 kiloliters. Choice B is incorrect as it incorrectly moves the decimal point. Choices C and D are significantly larger than the correct answer, indicating an incorrect conversion factor used.

Correct Answer: D

Rationale: When simplifying the expression 3x - 5x + 2, start by combining like terms. -5x is subtracted from 3x to give -2x. Adding 2 at the end gives the simplified expression -2x. Therefore, the correct answer is -2x. Choice A, -2x + 2, incorrectly adds 2 at the end. Choice B, -8x, incorrectly combines the coefficients of x without considering the constant term. Choice C, 2x + 2, incorrectly adds the coefficients of x without simplifying.

Correct Answer: C

Rationale: The mode of a data set is the value that appears most frequently. In this data set (2, 3, 3, 4, 4, 4, 5), the number 4 appears three times, which is more frequent than any other number in the set. Therefore, the correct answer is 4. Choice A (2), B (3), and D (5) do not appear as frequently as 4 in the data set, so they are not the mode.