Correct Answer: B

Rationale: To convert decimeters to centimeters, we use the conversion factor that 1 decimeter is equal to 10 centimeters. Setting up the proportion: 1/0.1 = x/2.5. Solving for x gives 2.5 = 0.1x, x = 25. Therefore, the width of the book in centimeters is 25. Choices A, C, and D are incorrect because they do not correctly convert decimeters to centimeters. A and D have decimal placement errors, and C has an incorrect magnitude of centimeters.

Correct Answer: C

Rationale: To convert kilometers to miles, you can use the conversion factor of approximately 0.62 miles per kilometer. Therefore, 45 kilometers 0.62 miles/kilometer = 27.9 miles, which is approximately 28 miles away. Choice A (42 miles), Choice B (37 miles), and Choice D (16 miles) are incorrect as they do not reflect the accurate conversion from kilometers to miles.

Correct Answer: C

Rationale: To find the perimeter of a hexagonal field with 6 sides, multiply the length of one side (320 feet) by the number of sides (6): 320 x 6 = 1920 feet. The total cost of the fencing material can be calculated by multiplying the perimeter by the cost per foot: 1920 feet x $1.75 = $3360. Therefore, the farmer will need to spend $3,360 on fencing material to enclose the perimeter of the field. Choice A, B, and D are incorrect as they do not accurately calculate the total cost based on the given measurements and cost per foot.

Correct Answer: D

Rationale: To arrange the numbers from least to greatest, first convert them to decimals: 1. 7/3 is approximately 2.33 2. 9/2 equals 4.5 3. 10/9 is approximately 1.11 4. 7/8 equals 0.875 Now, arrange the decimals from least to greatest: 0.875 (7/8), 1.11 (10/9), 2.33 (7/3), 4.5 (9/2). Therefore, the correct order is 7/8, 10/9, 7/3, 9/2. Choice A is incorrect because it doesn't follow the correct order. Choice B is incorrect as it places 9/2 before 7/3, which is not the right arrangement. Choice C is incorrect as it places 7/3 before 9/2 and 10/9, which is incorrect. Thus, the correct answer is choice D.

Correct Answer: B

Rationale: To convert decimeters to centimeters, we use the conversion factor that 1 decimeter is equal to 10 centimeters. Setting up the proportion: 1/0.1 = x/2.5. Solving for x gives 2.5 = 0.1x, x = 25. Therefore, the width of the book in centimeters is 25. Choices A, C, and D are incorrect because they do not correctly convert decimeters to centimeters. A and D have decimal placement errors, and C has an incorrect magnitude of centimeters.