Correct Answer: A

Rationale: To convert a decimal to a percent, move the decimal point two places to the right. Therefore, 0.0068 as a percentage is 0.68%. Choice A is correct because it represents the correct conversion. Choice B is incorrect as it would be the decimal 6.8 represented as a percentage. Choice C is incorrect as it would be the decimal 0.068 represented as a percentage. Choice D is incorrect as it is the original decimal value.

Correct Answer: A

Rationale: To convert a decimal to a percent, move the decimal point two places to the right. Therefore, 0.0068 as a percentage is 0.68%. Choice A is correct because it represents the correct conversion. Choice B is incorrect as it would be the decimal 6.8 represented as a percentage. Choice C is incorrect as it would be the decimal 0.068 represented as a percentage. Choice D is incorrect as it is the original decimal value.

Correct Answer: C

Rationale: To convert a percentage to a decimal, divide by 100. In this case, to convert 76.3% to a decimal, you move the decimal point two places to the left, resulting in 0.763. Therefore, the correct answer is C. Choice A (0.0763) is incorrect as it represents 7.63% as a decimal. Choice B (7) and Choice D (7.63) are not correct conversions of the given percentage to a decimal.

Correct Answer: D

Rationale: To find the volume of a pyramid, we use the formula: Volume = (1/3) * base area * height. First, calculate the base area by squaring the base side length: 10cm * 10cm = 100 sq cm. Substitute the values into the formula: Volume = (1/3) * 100 sq cm * 8cm = 80 cu cm. Therefore, the correct answer is 160 cu cm. Choices A, B, and C are incorrect because they do not correctly calculate the volume of the pyramid based on the given dimensions.

Correct Answer: D

Rationale: To find the value of x, cross multiply in the ratio 18:x=10:300. This gives 18 * 300 = 10 * x. Solving for x, x = 540. Therefore, the correct answer is D. Choice A (16), Choice B (180), and Choice C (30) are incorrect because they do not satisfy the proportion equation 18:x=10:300 when cross multiplied.