Solve for x: 3(x - 4) = 18.
- A. x = 10
- B. x = 12
- C. x = 5
- D. x = 3
Correct Answer: A
Rationale: To solve the equation, begin by distributing the 3 on the left side: 3x - 12 = 18. Next, add 12 to both sides to isolate x: 3x = 30. Finally, divide by 3 to determine the value of x: x = 10. Therefore, the correct answer is x = 10. Choice B, x = 12, is incorrect as the correct value of x is 10, not 12. Choice C, x = 5, is incorrect as it does not satisfy the equation after substitution. Choice D, x = 3, is incorrect as it does not fulfill the equation when substituted back.
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Given 15:x=3:8, find x.
- A. x=40
- B. x=20
- C. x=30
- D. x=10
Correct Answer: A
Rationale: To find x, we set up the proportion 15:x = 3:8. Cross multiply to get 15*8 = 3*x, which simplifies to 120 = 3x. Dividing by 3 on both sides gives x = 40. Therefore, x=40 is the correct answer. Choices B, C, and D are incorrect because they do not match the correct calculation. Option B results from incorrectly dividing 15 by 3 instead of multiplying it by 8. Option C comes from dividing 15 by 3, and Option D is the result of dividing 15 by 8 instead of multiplying by 3.
A set of integers can be classified as positive, negative, or zero. Which of the following statements about multiplying positive and negative integers is ALWAYS true?
- A. The product will always be positive.
- B. The product will always be negative.
- C. The product will depend on the specific positive and negative numbers used.
- D. Positive and negative integers cannot be multiplied.
Correct Answer: B
Rationale: When multiplying a positive integer by a negative integer, the product will always be negative. This is a fundamental rule of arithmetic. The sign of the product is determined by the rule that states a positive number multiplied by a negative number results in a negative number. Therefore, the statement that the product will always be negative is always true when multiplying positive and negative integers. Choice A is incorrect because the product is not always positive when multiplying positive and negative integers. Choice C is incorrect because the product is not dependent on the specific numbers but on the signs of the integers being multiplied. Choice D is incorrect as positive and negative integers can be multiplied.
X/4 = 9/x, solve for x.
- A. x = 6
- B. x = 3
- C. x = 9
- D. x = 2
Correct Answer: A
Rationale: To solve X/4 = 9/x, cross multiply to get x^2 = 36. Taking the square root of both sides gives x = 6. Choice A is correct because x = 6 satisfies the equation x^2 = 36. Choices B, C, and D are incorrect as they do not satisfy the equation when substituted back into it.
Stewart has 56 acres of land. He wants to divide the land into plots of 0.25 acres. How many plots of land will Stewart have after he divides the 56 acres?
- A. 224 plots
- B. 220 plots
- C. 210 plots
- D. 230 plots
Correct Answer: A
Rationale: To find the number of plots, divide 56 acres by 0.25 acres per plot: 56 · 0.25 = 224 plots. Therefore, Stewart will have 224 plots of land after dividing the 56 acres. The correct answer is A because dividing 56 acres by 0.25 acres per plot gives 224 plots, not 220, 210, or 230 plots.
What is the result of dividing 40.3 by 4.8?
- A. 7.5
- B. 8.4
- C. 6.2
- D. 9.1
Correct Answer: B
Rationale: To divide 40.3 by 4.8, you perform the calculation: 40.3 · 4.8 ≈ 8.4. Therefore, the correct answer is 8.4. Choice A (7.5) is incorrect as it is the result of dividing 40.3 by 5.4. Choice C (6.2) is incorrect as it is the result of dividing 40.3 by 6.5. Choice D (9.1) is incorrect as it is the result of dividing 40.3 by 4.4.