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What is the result of (6.4)(2.8) · 0.4? Which of the following is correct?
- A. 16.62
- B. 17.92
- C. 41.55
- D. 44.8
Correct Answer: D
Rationale: To simplify the expression, first multiply 6.4 by 2.8 to get 17.92. Then, divide the result by 0.4 to find the final answer. Therefore, (6.4)(2.8) · 0.4 equals 44.8. Choices A, B, and C are incorrect because they do not represent the correct result of the given expression.
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Solve the equation 8x − 6 = 3x + 24. Which of the following is the correct solution?
- A. x = 2.5
- B. x = 3.6
- C. x = 5
- D. x = 6
Correct Answer: D
Rationale: To solve the equation 8x − 6 = 3x + 24, start by adding 6 to both sides: 8x − 6 + 6 = 3x + 24 + 6, which simplifies to 8x = 3x + 30. Next, subtract 3x from both sides to get 5x = 30. Finally, divide both sides by 5 to solve for x: x = 6. Therefore, the correct solution is x = 6. Choices A, B, and C are incorrect because they do not result from the correct algebraic manipulation of the equation.
After taxes, a worker earned $15,036 in 7 months. What is the amount the worker earned in 2 months?
- A. $2,148
- B. $4,296
- C. $6,444
- D. $8,592
Correct Answer: B
Rationale: To find the amount earned in 2 months, set up a proportion using two ratios relating amount earned to months: (15,036/7) = (x /2). Cross-multiply and solve for x: 7x = 30,072, x = 4,296. Therefore, the worker earned $4,296 in 2 months. Choice A, $2,148, is incorrect as it is half of the correct answer. Choices C and D, $6,444 and $8,592, are incorrect as they do not correspond to the calculated proportion.
What is the result of the expression 102 - 7(3 - 4) - 25? Which of the following is correct?
- A. -12
- B. 2
- C. 68
- D. 82
Correct Answer: D
Rationale: To simplify the expression, we follow the order of operations (PEMDAS): Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right). First, solve inside the parentheses: 3 - 4 = -1. Then, multiply -1 by 7: -1 * 7 = -7. Now, substitute these values back into the expression: 102 - (-7) - 25 = 102 + 7 - 25 = 109 - 25 = 84. Therefore, the correct answer is 84. Choices A, B, and C are incorrect as they do not represent the correct simplification of the given expression.
A rectangular field has an area of 1452 square feet. If the length is three times the width, what is the width of the field?
- A. 22 feet
- B. 44 feet
- C. 242 feet
- D. 1452 feet
Correct Answer: A
Rationale: To find the width of the rectangular field, use the formula for the area of a rectangle: A = length width. Given that the length is three times the width, you have A = 3w w. Substituting the given area, 1452 = 3w^2. Solving for w, you get 484 = w^2. Taking the square root gives ±22, but since the width must be positive, the width of the field is 22 feet. Choice B, 44 feet, is incorrect because it represents the length, not the width. Choice C, 242 feet, is incorrect as it is not a factor of the area. Choice D, 1452 feet, is incorrect as it represents the total area of the field, not the width.
If m represents a car's average mileage in miles per gallon, p represents the price of gas in dollars per gallon, and d represents a distance in miles, which of the following algebraic equations represents the cost, c, of gas per mile?
- A. c = dp/m
- B. c = p/m
- C. c = mp/d
- D. c = m/p
Correct Answer: B
Rationale: The cost of gas per mile, c, is calculated by dividing the price of gas, represented by p, by the car's average mileage, represented by m. Therefore, the correct equation is c = p/m. Choice A (dp/m) incorrectly multiplies the price of gas and distance, while choice C (mp/d) incorrectly multiplies the average mileage and price of gas. Choice D (m/p) incorrectly divides the average mileage by the price of gas, which does not represent the cost of gas per mile.