Correct Answer: A

Rationale: To convert kilograms to grams, you need to multiply by 1,000 since there are 1,000 grams in a kilogram. Therefore, 7 kilograms is equal to 7 x 1,000 = 7,000 grams. The correct answer is 7000 grams. Choice B (70 grams) is incorrect as it represents the conversion of 7 kilograms to grams without considering the correct multiplier. Choice C (700 grams) is incorrect as it is a tenth of the correct conversion. Choice D (70,000 grams) is incorrect as it is ten times the correct conversion.

Correct Answer: C

Rationale: To find the total surface area of the box excluding the base, calculate the lateral surface area of the rectangular base and the surface area of the hemisphere. The lateral surface area of the rectangular base is 2(20cm x 15cm) = 600 sq cm. The surface area of the hemisphere is 2πr^2, where r is half the diameter of the base, so r = 10cm. Thus, the surface area of the hemisphere is 2π(10cm)^2 = 200π sq cm ≈ 628.32 sq cm. Add the lateral surface area of the base and the surface area of the hemisphere: 600 sq cm + 628.32 sq cm ≈ 1228.32 sq cm. Therefore, the total surface area of the box is approximately 1228.32 sq cm, which is closest to 1325 sq cm (Choice C). Choices A, B, and D are incorrect as they do not represent the accurate calculation of the total surface area of the box.

Correct Answer: A

Rationale: To solve the equation 3x + 2 = 14, first, subtract 2 from both sides to isolate 3x: 3x = 12. Then, divide by 3 to solve for x: x = 4. Therefore, the correct answer is A, x = 4. Choice B, x = 2, is incorrect because it does not satisfy the equation. Choice C, x = 6, is incorrect as well since it does not satisfy the equation. Choice D, x = 3, is also incorrect as it does not satisfy the given equation.

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: C

Rationale: To convert the fraction 7/8 to a decimal, you divide the numerator (7) by the denominator (8): 7 · 8 = 0.875. Therefore, the correct decimal representation of the fraction 7/8 is 0.875. Choice A and B, which are both 0.8, are incorrect as they represent 4/5 and not 7/8. Choice D, 0.9, is also incorrect as it represents 9/10 and not 7/8.