Correct Answer: A

Rationale: The correct answer is A, 50%. A standard six-sided die has three even numbers (2, 4, 6) out of six possible outcomes. The probability of rolling an even number is therefore 3 out of 6, which simplifies to 50%. Choices B, C, and D are incorrect because they do not accurately reflect the probability of rolling an even number on a six-sided die.

Correct Answer: B

Rationale: The correct answer is B: 5.73. When dividing 3.44 by 0.6, the calculation is 3.44 · 0.6 = 5.73. Choice A (11.41) is incorrect because it is the result of multiplying, not dividing. Choice C (2.33) and Choice D (0.57) are also incorrect results obtained by incorrect calculations.

Correct Answer: C

Rationale: In this scenario, to find the total amount of medication administered in 3 hours, we first calculate the total drops administered by multiplying the drops per minute by the total minutes. This gives us 40 drops/minute * 180 minutes = 7200 drops. Then, we convert the drops to milligrams by multiplying the total drops by the amount of medication in each drop, which is 1mg. Therefore, 7200 drops * 1mg/drop = 7200mg. The correct answer is 7,200mg. Choice A is incorrect as it miscalculates the total amount. Choice B is incorrect as it doubles the correct answer. Choice D is incorrect as it quadruples the correct answer.

Correct Answer: C

Rationale: To calculate the total number of words typed in 20 minutes, multiply the typing speed per minute (45 words) by the duration in minutes (20 minutes): 45 words/min 20 min = 900 words. Therefore, the correct answer is 900 words. Choices A, B, and D are incorrect because they do not reflect the accurate calculation based on the given information.

Correct Answer: D

Rationale: To calculate 75% of 80, you multiply 0.75 by 80, which equals 60. Therefore, the correct answer is 60. Choices A, B, and C are incorrect because they do not represent 75% of 80. Choice A (35) is close to 50% of 80, Choice B (45) is close to 56.25% of 80, and Choice C (70) exceeds 80.