Correct Answer: A

Rationale: To convert 0.3 to a fraction, we take 0.3 and express it as 3/10. This fraction is already in its simplest form because 3 and 10 do not have any common factors other than 1. Choice B, 1/3, is incorrect as it represents a different value. Choice C, 1/4, and Choice D, 1/5, are also incorrect as they do not match the equivalent fraction for 0.3.

Correct Answer: A

Rationale: The prefixes 'micro-' and 'milli-' represent 10^-6 and 10^-3, respectively. 'Micro-' denotes one-millionth (10^-6), while 'milli-' denotes one-thousandth (10^-3). Choice B is incorrect because it confuses the order of magnitudes for micro and milli. Choice C and D are also incorrect as they provide the wrong values for the prefixes micro and milli.

Correct Answer: A

Rationale: To convert 0.004 to a ratio, we first express it as 4/1000, which simplifies to 1/250. Hence, 0.004 is equivalent to the simplified ratio of 1:250. Choice B, 4:35, is incorrect as it does not reflect the correct conversion. Choice C, 7:28, is incorrect because it does not represent the simplified ratio of 0.004. Choice D, 4:00, is incorrect as it does not simplify to the original decimal value.

Correct Answer: A

Rationale: To convert 0.3 to a fraction, we take 0.3 and express it as 3/10. This fraction is already in its simplest form because 3 and 10 do not have any common factors other than 1. Choice B, 1/3, is incorrect as it represents a different value. Choice C, 1/4, and Choice D, 1/5, are also incorrect as they do not match the equivalent fraction for 0.3.

Correct Answer: A

Rationale: In the metric system, 'km' stands for kilometer, which is a unit of length equal to 1,000 meters. This choice is correct as 'kilometer' is the standard unit for measuring long distances. Choice B, 'kilomole,' is incorrect as it is a unit in chemistry representing a quantity of substance. Choice C, 'kilobyte,' is incorrect as it is a unit of digital information storage, not a unit of measurement. Choice D, 'knot,' is incorrect as it is a unit of speed used in navigation and aeronautics, not a unit of length in the metric system.