Convert 0.004 to a ratio.

Correct Answer: A

Rationale: To convert 0.004 to a ratio, we can express it as 4/1000, which simplifies to 1/250. Therefore, the correct ratio is 1:250. Choice B (4:200) is incorrect as it simplifies to 1:50, not 1:250. Choice C (2:400) simplifies to 1:200, which is also incorrect. Choice D (9:200) simplifies to a ratio greater than 1:1, which is not equivalent to 1:250.

Correct Answer: D

Rationale: To convert milligrams to micrograms, you need to multiply by 1000, not 10000. Therefore, to convert 0.075 mg to mcg, you multiply 0.075 by 1000, giving you 75 mcg. The correct answer is not provided in the choices, and the correct conversion is 75 mcg, which is not listed as an option. Choices A, B, and C are incorrect because they do not reflect the correct conversion factor. Choice D, 750 mcg, is a common mistake made by incorrectly adding a zero. It is important to remember that the conversion from milligrams to micrograms involves multiplying by 1000, not adding extra zeros.

Correct Answer: C

Rationale: To convert 0.16 into a fraction, you write it as 16\100, which simplifies to 4\25. This fraction is in its simplest form and accurately represents the original decimal value without further reduction. Choice A (16\1000) is incorrect because the fraction is not simplified, and Choice D (4\50) is incorrect as it simplifies to 2\25, not representing the original decimal value. Therefore, Choice C is the correct answer.

Correct Answer: B

Rationale: The decimal 0.2 is already at the nearest tenth, so it does not need to be rounded. Rounding to the nearest tenth means keeping one decimal place, which is already the case with 0.2. Therefore, the correct answer is 0.2, as it is already at the specified rounding point. Choices A, C, and D are incorrect because they represent values that are not the result of rounding 0.2 to the nearest tenth. 0.1 is rounding down, 0.3 is rounding up, and 0.25 is not the nearest tenth of 0.2.

Correct Answer: A

Rationale: To convert 0.26 to a fraction, we write it as 26/100. To simplify this fraction, we divide both the numerator and the denominator by their greatest common divisor, which is 2 in this case. Dividing 26 and 100 by 2 results in 13/50. Therefore, 0.26 as a fraction in simplest form is 13/50. Choice B (26/100) is the original form of the decimal, not simplified. Choice C (26/1000) is incorrect as it doesn't match the decimal representation. Choice D (1/4) is not the equivalent fraction for 0.26.