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The table below shows the number of books checked out from a library over the course of 4 weeks. Which equation describes the relationship between the number of books (b) and weeks (w)?
- A. b = 10w + 2
- B. b = 5w + 10
- C. b = 8w + 12
- D. b = 4w + 20
Correct Answer: B
Rationale: The relationship between the number of books and weeks is best described by the equation b = 5w + 10. This is because the initial value of books checked out is 10, which indicates that even with 0 weeks, there are already 10 books checked out. The rate at which books are checked out per week is 5, as indicated by the coefficient of w. Therefore, the correct equation should be b = 5w + 10. Choices A, C, and D are incorrect because they do not represent the correct initial value or rate of increase for the given scenario.
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How many cubic inches of water could the aquarium hold if it were filled completely? (Dimensions: 30 in 10 in 12 in)
- A. 3600 cubic inches
- B. 52 cubic inches
- C. 312 cubic inches
- D. 1144 cubic inches
Correct Answer: A
Rationale: To find the volume of the aquarium, we multiply its length, width, and height. The formula for the volume of a rectangular solid is V = l w h. Substituting the given dimensions, we get V = 30 10 12 = 3600 cubic inches. Therefore, the aquarium can hold 3600 cubic inches of water. Choice B (52 cubic inches), Choice C (312 cubic inches), and Choice D (1144 cubic inches) are incorrect as they do not correctly calculate the volume of the aquarium based on its dimensions.
Solve for x: 2x - 7 = 3
- A. x = 4
- B. x = 3
- C. x = -2
- D. x = 5
Correct Answer: D
Rationale: To solve the equation for x, follow these steps: 2x - 7 = 3. Add 7 to both sides to isolate 2x, resulting in 2x = 10. Then, divide by 2 on both sides to find x, which gives x = 5. Therefore, the correct answer is x = 5. Choices A, B, and C are incorrect because they do not accurately solve the equation.
Jonathan pays a $65 monthly flat rate for his cell phone. He is charged $0.12 per minute for each minute used in a roaming area. Which of the following expressions represents his monthly bill for x roaming minutes?
- A. 65 + 0.12x
- B. 65x + 0.12
- C. 65.12x
- D. 65 + 0.12x
Correct Answer: A
Rationale: The correct expression for Jonathan's monthly bill is 65 + 0.12x, where x represents the number of roaming minutes. The $65 monthly flat rate is added to the product of $0.12 per minute and the number of roaming minutes (x). Choice B is incorrect because it incorrectly multiplies the flat rate by x and adds the per-minute charge. Choice C is incorrect as it combines the flat rate and the per-minute charge into a single value. Choice D is incorrect as it incorrectly multiplies the flat rate by x and adds the per-minute charge separately.
A rectangular solid box has a square base with a side length of 5 feet and a height of h feet. If the volume of the box is 200 cubic feet, which of the following equations can be used to find h?
- A. 5h = 200
- B. 5h² = 200
- C. 25h = 200
- D. h = 200 · 5
Correct Answer: C
Rationale: The volume formula for a rectangular solid is V = l w h. In this case, the length and width are both 5 feet. Substituting the values into the formula gives V = 5 5 h = 25h = 200. Therefore, h = 200 · 25 = 8. Option A is incorrect because the product of length, width, and height is not directly equal to the volume. Option B is incorrect as squaring the height is not part of the volume formula. Option D is incorrect as it oversimplifies the relationship between height and volume, not considering the base dimensions.
On a floor plan drawn at a scale of 1:100, the area of a rectangular room is 30 cm². What is the actual area of the room?
- A. 30,000 cm²
- B. 300 m²
- C. 3,000 m²
- D. 30 m²
Correct Answer: D
Rationale: On a 1:100 scale drawing, each centimeter represents one meter. The area of the room in the scale drawing is 30 cm², which means the actual area is 30 m². Choice A (30,000 cm²) is incorrect as it doesn't account for the scale conversion. Choice B (300 m²) is incorrect because it multiplies the scale area directly by 10,000, which is not the correct conversion. Choice C (3,000 m²) is also incorrect as it applies the scale factor incorrectly.