Correct Answer: B

Rationale: To calculate a 20% decrease of 400 mg, you multiply 400 mg by 0.20 to get 80 mg. Subtracting 80 mg from the current dosage of 400 mg results in a new dosage of 320 mg. Choice A is incorrect because it miscalculates the decrease. Choice C is incorrect as it represents a 20% increase instead of a decrease. Choice D is incorrect as it represents the initial dosage, not the reduced dosage.

Correct Answer: B

Rationale: To calculate a 20% decrease of 400 mg, you multiply 400 mg by 0.20 to get 80 mg. Subtracting 80 mg from the current dosage of 400 mg results in a new dosage of 320 mg. Choice A is incorrect because it miscalculates the decrease. Choice C is incorrect as it represents a 20% increase instead of a decrease. Choice D is incorrect as it represents the initial dosage, not the reduced dosage.

Correct Answer: A

Rationale: To calculate the percent increase, subtract the initial value from the final value, which gives 2219 - 1432 = 787. Then, divide the increase (787) by the initial value (1432) and multiply by 100 to get the percentage: (787/1432) * 100 = 55%. Therefore, the approximate percent increase in the number of births is 55%. Choice B, 36%, is incorrect because it does not match the calculated increase. Choice C, 64%, is incorrect as it is higher than the actual percentage. Choice D, 42%, is incorrect as it is lower than the actual percentage.

Correct Answer: D

Rationale: To calculate the 30% increase, find 30% of 270 mg: 0.30 x 270 mg = 81 mg. Add this increase to the original dosage: 270 mg + 81 mg = 351 mg. Therefore, the patient's dosage after the 30% increase will be 351 mg. Choice A (81 mg) is incorrect as it only represents the calculated increase, not the total dosage post-increase. Choice B (270 mg) is the original dosage and does not account for the 30% increase. Choice C (300 mg) is the original dosage plus 30 mg, not the correct calculation with a 30% increase.

Correct Answer: D

Rationale: When multiplying two even integers and one odd integer, the product will always be even. This is because multiplying any number of even integers will always result in an even number. Therefore, the only possible product from the given options is 24, as it is the only even number listed. Choices A, B, and C are incorrect as they are all odd numbers, and the product of two even integers and one odd integer will never result in an odd number.