Simplify the following expression: 5 x 3 · 9 x 4

Correct Answer: A

Rationale: To simplify the expression 5 x 3 · 9 x 4, first perform the multiplications and divisions from left to right: 5 x 3 = 15 and 9 x 4 = 36. So, the expression becomes 15 · 36. When dividing fractions, multiply the first fraction by the reciprocal of the second fraction. Hence, 15 · 36 = 15/36. To simplify the fraction further, find the greatest common divisor, which is 3. Divide both the numerator and denominator by 3 to get the final result: 15/36 = 5/12. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not represent the correct simplification of the given expression.

Correct Answer: C

Rationale: To determine the highest percentage, we need to calculate each option. The percentage in answer A is: 50 / 250 x 100 = 20%. The percentage in answer B is: 57 / 250 x 100 = 22.8%. The percentage in answer C is: (74 + 55) / 433 x 100 = 29.8%. The percentage in answer D is: 21 / 183 x 100 = 11.5%. Therefore, the correct answer is C, as it has the highest percentage of doctors among the staff at both hospitals. Choices A, B, and D are incorrect as they have lower percentages compared to choice C.

Correct Answer: B

Rationale: The range is calculated as the difference between the largest and smallest values in a dataset. In this case, the largest number of flights made by the flight attendant in a month was 79, and the smallest number was 54. Therefore, the range is 79 - 54 = 25. Choices A, C, and D are incorrect as they do not reflect the correct calculation of the range based on the given data.

Correct Answer: C

Rationale: The range in the number of houses sold per year is calculated by subtracting the minimum number of houses sold from the maximum number of houses sold. In this case, the range is 42 (maximum) - 11 (minimum) = 31, not 29 as stated in the original rationale. Therefore, choice C (29) is incorrect. Choices A (20), B (25), and D (35) are also incorrect as they do not reflect the correct range of houses sold per year, which is 31.

Correct Answer: C

Rationale: The correct calculation to determine the medication dosage for a patient weighing 60 kg is: 5 mg/kg x 60 kg = 300 mg. Therefore, the patient should receive 300 mg of medication. Choice A (100 mg) is incorrect as it does not account for the patient's weight. Choice B (150 mg) is incorrect as it miscalculates the dosage. Choice D (400 mg) is incorrect as it overestimates the dosage based on the patient's weight.