Correct Answer: B

Rationale: To solve the equation x + x * x - x / x, follow the order of operations (PEMDAS/BODMAS). First, perform the multiplication: x * x = x^2. Then, perform the division: x / x = 1. Substituting these back into the equation gives x + x^2 - 1. Therefore, the equation simplifies to x + x^2 - 1. By evaluating this further, the final result is 3. Choices A, C, and D are incorrect because they do not correctly apply the order of operations to solve the equation.

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 calculate the total cost with the financing plan, multiply $120 by 24 months to get $2,880. Adding the $1,000 down payment gives a total of $3,880. By comparing this total with the initial cost of $2,600 when paying in cash, the man would pay $1,280 more with the financing plan. Choice A, $1,480 more, is incorrect because it miscalculates the additional amount. Choice C, $1,600 more, is incorrect as it overestimates the extra cost. Choice D, $2,480 more, is incorrect as it significantly overstates the additional payment.

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: 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.