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?

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.

Correct Answer: C

Rationale: To find the side length of the square, we take the square root of the area: √5625 ft² = 75 ft. The perimeter of a square is 4 times its side length, so the fencing needed is 4 75 ft = 300 ft. Therefore, Melissa needs 300 feet of fencing to enclose the square area of 5625 square feet. Option A (75 feet) is the side length of the square, not the fencing needed. Option B (150 feet) is half of the correct answer and does not account for all sides of the square. Option D (5,625 feet) is the total area, not the length of fencing required.

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.

Correct Answer: C

Rationale: To round 2.7834 to the nearest tenth, we look at the digit in the hundredths place, which is 8. Since 8 is greater than or equal to 5, the digit in the tenths place is rounded up. Therefore, 2.7834 rounded to the nearest tenth is 2.8. Choice A (2.7) is incorrect because rounding down would require the digit in the hundredths place to be less than 5. Choice B (2.78) is incorrect because rounding to the nearest tenth involves considering the digit in the hundredths place. Choice D (2.88) is incorrect as it goes beyond rounding to just the nearest tenth.

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.

Correct Answer: D

Rationale: To determine the correct order from least to greatest, start by simplifying the expressions. 2^(-1) = 1/2 and (-1)^3 = -1. Now, comparing the values, (-4/3) is the most negative, followed by -1, then (2/5), and finally 1/2. Therefore, the correct order is (-4/3), (-1)^3, (2/5), 2^(-1), making choice D the correct answer. Choices A, B, and C are incorrect because they do not follow the correct order from least to greatest as determined by comparing the values of the expressions after simplification.

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.

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.

Correct Answer: D

Rationale: To solve for x, multiply both sides by the reciprocal of 5/4 to isolate x. (4/5)(5/4)x = (4/5)20; x = 16. Therefore, the correct answer is 32. Choice A (8), Choice B (16), and Choice C (24) are incorrect as they do not represent the correct value of x obtained after correctly simplifying the expression.