Nokea
What is the area of a rectangle with a length of 5 cm and a width of 4 cm?
- A. 9 cm²
- B. 20 cm²
- C. 10 cm²
- D. 25 cm²
Correct Answer: B
Rationale: To find the area of a rectangle, you multiply its length by its width. In this case, the length is 5 cm and the width is 4 cm. So, Area = length * width = 5 cm * 4 cm = 20 cm². Therefore, the correct answer is 20 cm². Choice A (9 cm²), Choice C (10 cm²), and Choice D (25 cm²) are incorrect as they do not result from the correct calculation of multiplying the length and width of the rectangle.
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Your measurement of the width of a door is 36 inches. The actual width of the door is 35.75 inches. What is the relative error in your measurement?
- A. 0.70%
- B. 0.01%
- C. 0.99%
- D. 0.10%
Correct Answer: A
Rationale: To calculate relative error, you use the formula: (|measured value - actual value| / actual value) * 100%. Substituting the values, we get (|36 - 35.75| / 35.75) * 100% = (0.25 / 35.75) * 100% = 0.7%. This means your measurement is off by 0.7% from the actual width of the door. Choice B, 0.01%, is too small as it doesn't reflect the actual difference. Choices C and D are significantly different from the calculated answer and do not represent the accurate relative error in the measurement.
What number is 6 equal to 30% of?
- A. 18
- B. 20
- C. 24
- D. 26
Correct Answer: A
Rationale: To find the number that is 30% of 6, you can set up the equation 0.3x = 6. Solving for x gives x = 6 / 0.3 = 20. Therefore, 6 is equal to 30% of 20.
Choice B, 20, is incorrect as it is the result of the calculation. Choice C, 24, and Choice D, 26, are incorrect as they are not the numbers that 6 is equal to 30% of.
What number is 20 equal to 40% of?
- A. 50
- B. 8
- C. 200
- D. 5000
Correct Answer: A
Rationale: To find the number that 20 is equal to 40% of, you can set up the equation: 20 = 0.4 * x, where x is the unknown number. To solve for x, divide both sides of the equation by 0.4. This gives x = 20 / 0.4 = 50. Therefore, 20 is 40% of 50.
Choice B, 8, is incorrect because 20 is not equal to 40% of 8. Choice C, 200, is incorrect because 20 is not equal to 40% of 200. Choice D, 5000, is incorrect because 20 is not equal to 40% of 5000. The correct answer is 50.
Which of the following equations does not represent a function?
- A. y = x^2
- B. y = sqrt(x)
- C. x = y^2
- D. y = 2x + 1
Correct Answer: C
Rationale: An equation represents a function if each input (x-value) corresponds to exactly one output (y-value). In the equation x = y^2, for a single x-value, there are two possible y-values (positive and negative square root), violating the definition of a function. This violates the vertical line test, where a vertical line intersects the graph in more than one point for non-functions. Choices A, B, and D all pass the vertical line test and represent functions, making them incorrect answers.
What is the median of the set of numbers {2, 3, 9, 12, 15}?
- A. 3
- B. 9
- C. 12
- D. 15
Correct Answer: B
Rationale: The median represents the middle value in an ordered set of numbers. To find the median, the numbers need to be arranged in ascending order: {2, 3, 9, 12, 15}. Since the set has an odd number of elements, the median will be the middle value, which is 9 in this case. Choice A (3) and Choice D (15) are incorrect as they do not fall in the middle of the ordered set. Choice C (12) is also incorrect as it is not the middle value in this particular set.