Nokea
Evaluate the expression -3 x 5.
- A. -15
- B. -2
- C. 2
- D. 15
Correct Answer: A
Rationale: The correct answer is A, which is -15. When you multiply -3 by 5, you get -15. The negative sign in front of the 3 indicates a negative value, and when multiplied by a positive number like 5, the result remains negative. Choices B, C, and D are incorrect because they do not reflect the correct multiplication of -3 and 5.
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Which proportion yields a different number for the unknown compared to the others?
- A. 2/3 = x/6
- B. 4/5 = x/10
- C. 3/4 = x/8
- D. 5/6 = x/12
Correct Answer: D
Rationale: To find the value of x in each proportion, cross multiply. For proportion A, x = 4; for B, x = 8; for C, x = 6; and for D, x = 10. Hence, proportion D yields a different value for x compared to the others. Choices A, B, and C all result in unique values for x, but these values are distinct from the value obtained in proportion D.
Solve the system of equations.
Equation 1: 2x + y = 0
Equation 2: x - 2y = 8
- A. (1.8, 3.6) and (-1.8, -3.6)
- B. (1.8, -3.6) and (-1.8, 3.6)
- C. (1.3, 2.6) and (-1.3, -2.6)
- D. (-1.3, 2.6) and (1.3, -2.6)
Correct Answer: B
Rationale: From Equation 1: 2x + y = 0. Solve for y: y = -2x. Substitute y = -2x into Equation 2: x - 2(-2x) = 8. Simplify to x + 4x = 8, then 5x = 8, and x = 8 · 5 = 1.6. Substitute x = 1.6 back into y = -2x to find y = -3.2. Therefore, one solution is (1.6, -3.2). To find the second solution, use -1.6 for x to get (-1.6, 3.2). Thus, the correct answer is B, representing the solutions (1.8, -3.6) and (-1.8, 3.6). Choices A, C, and D contain incorrect values that do not match the solutions derived from solving the system of equations.
Solve |x| = 10.
- A. -10, 10
- B. -11, 11
- C. -12, 12
- D. -13, 13
Correct Answer: A
Rationale: The absolute value of x is equal to 10 when x is either -10 or 10. Therefore, the correct answer is A. Choices B, C, and D are incorrect because they do not satisfy the equation |x| = 10. For choice B, -11 and 11 do not satisfy the condition. Choices C and D also do not provide solutions that meet the equation's requirement.
Half of a circular garden with a radius of 11.5 feet needs weeding. Find the area in square feet that needs weeding. Round to the nearest hundredth. Use 3.14 for π.
- A. 207.64
- B. 415.27
- C. 519.08
- D. 726.73
Correct Answer: B
Rationale: The area of a circle is given by the formula A = π r², where r is the radius. Since only half of the garden needs weeding, we calculate half the area.
Using the given value of π (3.14) and a radius of 11.5 feet:
A = 0.5 3.14 (11.5)²
A = 0.5 3.14 132.25
A = 0.5 415.27
A = 207.64 square feet.
Thus, the area that needs weeding is approximately 207.64 square feet, making option B the correct answer.
Choice A (207.64) is incorrect as it represents the total area of the circular garden, not just half of it. Choice C (519.08) and Choice D (726.73) are also incorrect as they do not reflect the correct calculation for finding the area of half the circular garden.
How many gallons are in 1,000 fluid ounces?
- A. 7.8125 gallons
- B. 15.625 gallons
- C. 31.25 gallons
- D. 62.5 gallons
Correct Answer: A
Rationale: To convert fluid ounces to gallons, you need to divide the number of fluid ounces by the number of fluid ounces in a gallon. Since there are 128 fluid ounces in a gallon, to find out how many gallons are in 1,000 fluid ounces, you divide 1,000 by 128. The correct calculation is 1,000 / 128 = 7.8125 gallons. Therefore, the correct answer is A. Choices B, C, and D are incorrect as they do not accurately represent the conversion from fluid ounces to gallons.