Nokea
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.
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How many kiloliters are in 147 liters?
- A. 0.147 kiloliters
- B. 1.47 kiloliters
- C. 1,470 kiloliters
- D. 147,000 kiloliters
Correct Answer: A
Rationale: To convert liters to kiloliters, divide by 1000 since there are 1000 liters in a kiloliter. Therefore, 147 liters = 0.147 kiloliters. Choice B is incorrect as it incorrectly moves the decimal point. Choices C and D are significantly larger than the correct answer, indicating an incorrect conversion factor used.
Which decimal is the smallest?
- A. 2.22
- B. 2.02
- C. 2.002
- D. 2.2
Correct Answer: C
Rationale: To determine the smallest decimal, we look at the digits after the decimal point. In this case, 2.002 is the smallest because it has the least value in the thousandths place. Choice A, 2.22, has a higher value in the hundredths place making it larger. Choice B, 2.02, has a higher value in the hundredths place compared to 2.002. Choice D, 2.2, is larger than 2.002 as it has a higher value in the tenths place.
What is the difference between two equal numbers?
- A. Negative
- B. Positive
- C. Zero
- D. Not enough information
Correct Answer: C
Rationale: The difference between two numbers is found by subtracting one from the other. When two numbers are equal, subtracting them results in 0, because any number minus itself is always 0. Therefore, the difference between two equal numbers is always zero, making option C the correct answer. Option A ('Negative') and option B ('Positive') are incorrect as they do not represent the result of subtracting two equal numbers, which always yields zero. Option D ('Not enough information') is also incorrect as the difference between two equal numbers is definitively known to be zero.
Solve the equation for the unknown. 3x + 2 = 20
- A. x = 2
- B. x = 4
- C. x = 6
- D. x = 8
Correct Answer: C
Rationale: Simplify the equation step by step:
Subtract 2 from both sides:
3x + 2 - 2 = 20 - 2
3x = 18
Divide both sides by 3:
x = 18 · 3
x = 6
Therefore, the correct answer is C (x = 6).
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.