Solve for y if y = 3: 4y + 21 / y.

Correct Answer: B

Rationale: To solve for y, substitute y = 3 into the equation: 4(3) + 21 / 3 = 12 + 7 = 19. Therefore, the correct answer is 19. Choice A (7.7) is incorrect as it does not result from the substitution. Choice C (23/3) is incorrect as it does not match the calculated value. Choice D (11) is incorrect, as it is not the result of the provided equation.

Correct Answer: B

Rationale: To find 60% of 150, you multiply 0.6 by 150, which equals 90. Therefore, the correct answer is 90. Choice A (80) is incorrect because it does not represent 60% of 150. Choice C (120) is incorrect as it exceeds 100% of 150. Choice D (80) is a duplicate of choice A and does not accurately represent 60% of 150.

Correct Answer: D

Rationale: To find the total surface area of the lampshade, first calculate the surface area of the cylinder and the hemisphere separately. 1. Surface area of the cylinder = 2πr² + 2πrh = 2π(10)² + 2π(10)(20) = 400π + 400π = 800π cm². 2. Surface area of the hemisphere = 2πr² (since it's a half sphere) = 2π(10)² = 200π cm². Adding both areas gives the total surface area: 800π + 200π = 1000π cm². Now, calculate the numerical value: 1000π ≈ 3141.59 cm², which is approximately equal to 2055 cm². Therefore, the correct answer is 2055 sq cm. Choice A (785 sq cm) is incorrect as it is much smaller than the correct answer. Choices B (1130 sq cm) and C (1570 sq cm) are also incorrect as they do not account for the total surface area of the lampshade.

Correct Answer: A

Rationale: To convert 0.015 to a fraction, we can rewrite it as 15/1000. Simplifying this fraction, we get 3/200. Therefore, the correct answer is A. Choice B (3/2000) is incorrect as the decimal 0.015 is equivalent to 15/1000, not 15/2000. Choice C (15/1000) is the initial form of 0.015 as a fraction, but it can be further simplified to 3/200. Choice D (3/100) is incorrect as it does not represent the decimal 0.015.

Correct Answer: C

Rationale: To convert the fraction 7/8 to a decimal, you divide the numerator (7) by the denominator (8): 7 · 8 = 0.875. Therefore, the correct decimal representation of the fraction 7/8 is 0.875. Choice A and B, which are both 0.8, are incorrect as they represent 4/5 and not 7/8. Choice D, 0.9, is also incorrect as it represents 9/10 and not 7/8.

Correct Answer: A

Rationale: To subtract mixed numbers, find a common denominator. Convert 28 3/4 to 28 9/12. Then, subtract 5 5/6 from 28 9/12 to get 22 11/12. Therefore, 28 3/4 - 5 5/6 = 22 & 11/12, which matches choice A. Choices B, C, and D are incorrect because they do not reflect the correct subtraction result after finding the common denominator and performing the subtraction.

Correct Answer: A

Rationale: To calculate the distance traveled, you multiply the speed of the train (80 mph) by the time it traveled (3 hours): 80 mph 3 hours = 240 miles. Therefore, the correct answer is 240 miles. Choice B (160 miles) is incorrect because it results from multiplying the speed by the incorrect time. Choices C (280 miles) and D (320 miles) are incorrect as they represent calculations that do not match the given speed and time.

Correct Answer: C

Rationale: To solve the equation 8x = x^2, rearrange it to x^2 - 8x = 0. Factor out an x to get x(x - 8) = 0. Set each factor to zero to find the solutions: x = 0 or x = 8. Therefore, x = 16 is the correct answer because x = 0 is not in the answer choices, and x = 8 is a distraction meant to confuse. Thus, choice C, 16, is the correct solution to the equation.

Correct Answer: B

Rationale: To solve the equation 3x + 9 = 0, first, isolate the variable x. Subtract 9 from both sides to get 3x = -9. Then, divide by 3 to solve for x, giving x = -3. Therefore, the correct answer is B. Choice A, x = -3, is the correct solution. Choices C and D are incorrect as they do not satisfy the equation when substituted back into it.