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Which of the following is the correct solution to the equation 3x + 4 = 19?
- A. x = 3
- B. x = 4
- C. x = 5
- D. x = 6
Correct Answer: C
Rationale: To solve the equation 3x + 4 = 19, first, subtract 4 from both sides to isolate the term with x, which gives 3x = 15. Then, divide both sides by 3 to solve for x, resulting in x = 5. Therefore, the correct answer is x = 5. Choice A, x = 3, is incorrect as it does not satisfy the equation. Choice B, x = 4, is also incorrect as it does not make the equation true. Choice D, x = 6, is incorrect as it does not align with the correct solution obtained through the proper algebraic steps.
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What is the area of a triangle with a base of 10 cm and a height of 7 cm?
- A. 70 cm²
- B. 35 cm²
- C. 140 cm²
- D. 100 cm²
Correct Answer: B
Rationale: To find the area of a triangle, you use the formula A = 1/2 base height. Substituting the given values: A = 1/2 10 cm 7 cm = 35 cm². Therefore, the correct answer is B. Choice A (70 cm²) is incorrect as it seems to be the product of the base and height rather than the area formula. Choice C (140 cm²) is incorrect as it appears to be twice the correct answer, possibly a result of a miscalculation. Choice D (100 cm²) is incorrect as it does not reflect the correct calculation based on the given base and height values.
x · 7 = x − 36. Solve the equation. Which of the following is correct?
- A. x = 6
- B. x = 42
- C. x = 4
- D. x = 252
Correct Answer: B
Rationale: To solve the equation x · 7 = x − 36, start by multiplying both sides by 7 to get 7(x · 7) = 7(x − 36), which simplifies to x = 7x − 252. Next, subtract 7x from both sides to get -6x = -252. Finally, divide both sides by -6 to solve for x, which results in x = 42. Therefore, the correct answer is x = 42. Choice A (x = 6), Choice C (x = 4), and Choice D (x = 252) are incorrect as they do not align with the correct solution derived from the equation.
Adam is painting the outside of a 4-walled shed. The shed is 5 feet wide, 4 feet deep, and 7 feet high. Which of the following is the amount of paint Adam will need for the four walls?
- A. 80 ft²
- B. 126 ft²
- C. 140 ft²
- D. 560 ft²
Correct Answer: B
Rationale: To find the amount of paint needed for the four walls of the shed, calculate the total area of the four walls. The shed has two pairs of identical walls. The area of one pair of walls is 5 feet (width) x 7 feet (height) + 4 feet (depth) x 7 feet (height) = 35 ft² + 28 ft² = 63 ft². Since there are two pairs of walls, the total area for the four walls is 2 x 63 ft² = 126 ft². Therefore, Adam will need 126 ft² of paint for the four walls. Choice A, 80 ft², is incorrect as it does not account for the total surface area of all four walls. Choice C, 140 ft², is incorrect as it overestimates the area required. Choice D, 560 ft², is incorrect as it significantly overestimates the amount of paint needed for the shed.
4 − 1/(22) + 24 · (8 + 12). Simplify the expression. Which of the following is correct?
- A. 1.39
- B. 2.74
- C. 4.95
- D. 15.28
Correct Answer: C
Rationale: First, complete the operations in parentheses: 4 − (1/22) + 24 · 20. Next, simplify the exponents: 4 − (1/22) + 24 · 20 = 4 − (1/4) + 24 · 20. Then, complete multiplication and division operations: 4 − (1/4) + 24 · 20 = 4 − 0.25 + 1.2. Finally, complete addition and subtraction operations: 4 − 0.25 + 1.2 = 4.95. Choice A, 1.39, is incorrect as it does not match the correct calculation. Choice B, 2.74, is incorrect as it is not the result of the given expression. Choice D, 15.28, is incorrect as it is not the correct simplification of the initial expression.
A student gets 42 questions out of 48 correct on a quiz. What is the percentage of questions that the student answered correctly?
- A. 1.14%
- B. 82.50%
- C. 85.00%
- D. 87.50%
Correct Answer: D
Rationale: To find the percentage of questions answered correctly, divide the number of correct questions by the total number of questions: 42/48 = 0.875. Multiply the result by 100 to express it as a percentage, which gives 87.5%. Therefore, the correct answer is 87.50%. Choice A (1.14%) is incorrect as it does not reflect the correct percentage. Choices B (82.50%) and C (85.00%) are also incorrect as they do not align with the calculation based on the given information.