Correct Answer: B

Rationale: To convert decimeters to centimeters, you need to multiply by 10 since 1 decimeter is equal to 10 centimeters. Therefore, to find the width of the book in centimeters, multiply 5 decimeters by 10: 5 decimeters * 10 = 50 centimeters. This means the width of the book is 50 centimeters, making choice B, "25 centimeters," the correct answer. Choices A, C, and D are incorrect because they do not correctly convert decimeters to centimeters.

Correct Answer: A

Rationale: To find the volume of a sphere, the formula V = (4/3)πr³ is used, where r is the radius of the sphere. Given that the diameter of the ball is 7 inches, the radius (r) would be half of the diameter, which is 3.5 inches. Plugging this value into the formula: V = (4/3)π(3.5)³ = (4/3)π(42.875) ≈ 165.7 in³. Therefore, the correct answer is A. Choice B, C, and D are incorrect as they do not accurately represent the volume of the ball with a diameter of 7 inches.

Correct Answer: B

Rationale: To qualify for an academic scholarship, Joshua needs to answer at least 80% of the 30 test questions correctly. 80% of 30 is 24, so Joshua must answer at least 24 questions correctly to qualify for the scholarship. Choice A (23) is incorrect as it is below the minimum required percentage. Choices C (26) and D (27) are also incorrect as they exceed the minimum number of questions Joshua needs to answer correctly for the scholarship.

Correct Answer: B

Rationale: To find the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost, we set up the inequality 400x >= 3000 + 100x. Simplifying this inequality gives 300x >= 3000, and dividing by 300 results in x >= 10. Therefore, at least 15 computers must be shipped and sold to cover the shipping cost, making choice B the correct answer. Choices A, C, and D are incorrect as they represent numbers less than 15, which would not cover the shipping cost.

Correct Answer: C

Rationale: Out of all the patients who took the antibiotic, 30% developed an infection. Among those with infections, 5% required hospitalization. To find the percentage of all patients hospitalized, we multiply the two percentages: 30% * 5% = 1.5%. Therefore, 1.5% of all patients were hospitalized. Choice A (1.50%) is the calculated percentage of all patients hospitalized, not 1.50%. Choice B (5%) is the percentage of patients who developed an infection and required hospitalization, not all patients. Choice D (30%) represents the initial percentage of patients who developed an infection, not the percentage hospitalized.