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 result of (4.71 10^3) - (2.98 10^2)? Which of the following is the correct simplified expression?
- A. 1.73 10
- B. 4.412 10^2
- C. 1.73 10^3
- D. 4.412 10^3
Correct Answer: D
Rationale: The correct answer is D: 4.412 10^3. To simplify the expression, rewrite 4.71 10^3 as 47.1 10^2. Subtract the values in front of 10^2: 47.1 - 2.98 = 44.12. Rewriting this gives 44.12 10^2 = 4.412 10^3. Choice A is incorrect as it does not account for the correct subtraction result. Choice B is incorrect as it does not correctly simplify the expression. Choice C is incorrect as it provides an incorrect power of 10 in the simplified 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.
A sandwich shop earns $4 for every sandwich (s) it sells, $2 for every drink (d), and $1 for every cookie (c). If this is all the shop sells, which of the following equations represents what the shop's revenue (r) is over three days?
- A. r = 4s + 2d + 1c
- B. r = 8s + 4d + 2c
- C. r = 12s + 6d + 3c
- D. r = 16s + 8d + 4c
Correct Answer: A
Rationale: Let s be the number of sandwiches sold. Each sandwich earns $4, so selling s sandwiches at $4 each results in revenue of $4s. Similarly, d drinks at $2 each give $2d of income, and cookies bring in $1c. Summing these values gives total revenue = 4s + 2d + 1c. Therefore, option A, r = 4s + 2d + 1c, correctly represents the shop's revenue. Choices B, C, and D are incorrect because they incorrectly multiply the prices of each item by more than one day's sales, which would overstate the total revenue for a three-day period.
Simplify the expression. Which of the following is correct? (52(3) + 3(-2)^2 / 4 + 3^2 - 2(5 - 8))
- A. 9/8
- B. 87/19
- C. 9
- D. 21/2
Correct Answer: B
Rationale: To simplify the expression, apply the order of operations (PEMDAS). Begin by squaring -2 to get 4. Then perform the multiplication and subtraction within parentheses: 52(3) + 3(4)/4 + 9 - 2(5 - 8) = 156 + 12/4 + 9 - 2(3) = 156 + 3 + 9 - 6 = 168 + 3 - 6 = 171 - 6 = 165. Therefore, the correct simplified expression is 165, which is equivalent to 87/19. Choices A, C, and D are incorrect because they do not represent the accurate simplification of the given expression.
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.