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A book has a width of 2.5 decimeters. What is the width of the book in centimeters?
- A. 0.25 centimeters
- B. 25 centimeters
- C. 250 centimeters
- D. 0.025 centimeters
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.
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Solve for y: 2y + 5 = 25 * 10
- A. y = 25
- B. y = 100
- C. y = 150
- D. y = 200
Correct Answer: B
Rationale: To solve the equation 2y + 5 = 25 * 10, start by simplifying the right side: 25 * 10 = 250. Then, subtract 5 from both sides to isolate 2y: 2y = 250 - 5 = 245. Finally, divide by 2 to find the value of y: y = 245 / 2 = 122.5. Therefore, the correct answer is y = 122.5. Choices A, C, and D are incorrect as they do not result from the correct calculation steps.
Joshua has to earn more than 92 points on a state test to qualify for a scholarship. Each question is worth 4 points, and the test has 30 questions. Which inequality can be solved to determine the number of questions Joshua must answer correctly?
- A. 4x < 30
- B. 4x < 92
- C. 4x > 30
- D. 4x > 92
Correct Answer: D
Rationale: Joshua must answer more than 92 points' worth of questions. Since each question is worth 4 points, the inequality is 4x > 92. Choice A (4x < 30) is incorrect as it represents that Joshua must answer less than 30 questions correctly, not earning more than 92 points. Choice B (4x < 92) is incorrect as it signifies that Joshua must earn less than 92 points, which contradicts the requirement. Choice C (4x > 30) is incorrect as it implies that Joshua must answer more than 30 questions correctly, but the threshold is 92 points, not 30 points.
Simplify the following expression: (3)(-4) + (3)(4) - 1
- A. -1
- B. 1
- C. 23
- D. 24
Correct Answer: A
Rationale: To solve the expression, first calculate the multiplication: (3)(-4) = -12 and (3)(4) = 12. Then, substitute the results back into the expression: (-12) + 12 - 1 = -1. Therefore, the correct answer is A. Choices B, C, and D are incorrect as they do not result from the correct calculations of the given expression.
Complete the following equation: 2 + (2)(2) - 2 · 2 = ?
- A. 5
- B. 3
- C. 2
- D. 1
Correct Answer: A
Rationale: To solve the equation, follow the order of operations (PEMDAS/BODMAS): Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).
1. Calculate inside the parentheses first: (2)(2) = 4.
2. Then, perform multiplication and division: 2 + 4 - 1 = 6 - 1 = 5.
Therefore, the correct answer is 5.
Choice B (3) is incorrect because multiplication is done before subtraction. Choices C (2) and D (1) are incorrect as they do not follow the correct order of operations to solve the equation.
A mathematics test has a 4:2 ratio of data analysis problems to algebra problems. If the test has 18 algebra problems, how many data analysis problems are on the test?
- A. 24
- B. 28
- C. 36
- D. 38
Correct Answer: C
Rationale: The ratio of 4:2 simplifies to 2:1. This means that for every 2 algebra problems, there is 1 data analysis problem. If there are 18 algebra problems, we can set up a proportion: 2 algebra problems correspond to 1 data analysis problem. Therefore, 18 algebra problems correspond to x data analysis problems. Solving the proportion, x = 18 * 1 / 2 = 9. Hence, there are 9 data analysis problems on the test. Therefore, the total number of data analysis problems on the test is 18 (algebra problems) + 9 (data analysis problems) = 27.