Correct Answer: A

Rationale: The probability of rolling a specific number on a six-sided die is calculated by dividing the favorable outcomes (rolling a 3) by the total possible outcomes. In this case, there is 1 favorable outcome (rolling a 3) out of 6 total possible outcomes (numbers 1 to 6 on the die). Therefore, the probability of rolling a 3 is 1/6. Choice B (1/4), C (1/3), and D (1/2) are incorrect because they do not represent the correct calculation of the probability for rolling a 3 on a six-sided die.

Correct Answer: D

Rationale: To find the result of subtracting 8.4 from 3.7, you need to subtract 3.7 from 8.4. Performing this subtraction, 8.4 - 3.7 equals 4.7. Therefore, the correct answer is 4.7. Choice A, 4.5, is incorrect as it is not the result of subtracting 8.4 from 3.7. Choices B and C, 4.8 and 4.6 respectively, are also incorrect as they do not match the correct subtraction result of 4.7.

Correct Answer: A

Rationale: To convert grams to kilograms, divide by 1,000 because there are 1,000 grams in a kilogram. Therefore, 4,000 grams · 1,000 = 4 kilograms. Choice A is correct as it represents the correct conversion. Choice B, 5 kilograms, is incorrect because it is not the result of dividing 4,000 grams by 1,000. Choice C, 1 kilogram, is incorrect because 4,000 grams is more than 1 kilogram. Choice D, 2 kilograms, is incorrect as it is not the correct conversion from grams to kilograms.

Correct Answer: B

Rationale: To solve the equation 3x + 9 = 0, first, isolate the variable x. Subtract 9 from both sides to get 3x = -9. Then, divide by 3 to solve for x, giving x = -3. Therefore, the correct answer is B. Choice A, x = -3, is the correct solution. Choices C and D are incorrect as they do not satisfy the equation when substituted back into it.

Correct Answer: C

Rationale: To convert ounces to pounds, divide the number of ounces by 16 since there are 16 ounces in a pound. Therefore, 192 ounces · 16 = 12 pounds. Choice A, 16 pounds, is incorrect because it does not represent the correct conversion from ounces to pounds. Choice B, 10 pounds, is incorrect as it is not the result of dividing 192 ounces by 16. Choice D, 16 pounds, is the same as choice A and is incorrect in the context of this conversion.