Correct Answer: A

Rationale: After 35% of the staff are on vacation, 65% remain. Since 20% of the remaining staff are certified, you multiply 0.20 by 65% (0.20 * 65% = 0.13 or 13%). Therefore, the correct answer is 0.13 or 13%. Choices C and D are incorrect as they do not represent the correct calculation for the percentage of certified staff available. Choice B is incorrect because it incorrectly states the calculated percentage as 0.13 instead of 0.07.

Correct Answer: A

Rationale: To calculate the population increase, multiply the current population by 1 plus the percentage increase. So, 1,000 * 1.05 = 1,050 people. Therefore, the correct answer is A. Choice B (1,200 people) is incorrect because it represents a 20% increase from the current population, not 5%. Choice C (1,100 people) is incorrect as it reflects a 10% increase, not a 5% increase. Choice D (1,300 people) is incorrect, showing a 30% increase, which is not the scenario given.

Correct Answer: B

Rationale: To find the number of girls in the class, we need to calculate 40% of the total number of students, which is 30. 40% of 30 is 0.40 * 30 = 12 girls. Therefore, there are 12 girls in the class. Choice A, 18 girls, is incorrect as it miscalculates the percentage. Choice C, 15 girls, is incorrect as it misrepresents the correct calculation. Choice D, 10 girls, is incorrect as it underestimates the number of girls in the class.

Correct Answer: C

Rationale: Out of the 100 patients, 30% were men, which equals 30 male patients. It is given that 10% of the men were overweight as children, so 10% of 30 is 3, meaning 3 male patients were overweight. Therefore, the remaining 27 male patients were not overweight as children. Choice A, B, and D are incorrect as they do not accurately represent the number of male patients who were not overweight.

Correct Answer: C

Rationale: Out of the 100 students, 3/4 (75 students) major in nursing. Since 1/3 of those students complete the program, 1/3 * 75 = 25 students will complete the program. Therefore, 25 students out of the 100 incoming class will complete the program, making choice C (15) the correct answer. Choices A, B, and D are incorrect as they do not reflect the correct calculation based on the given information.