Nokea
You measure the width of your door to be 36 inches. The true width of the door is 75 inches. What is the relative error in your measurement?
- A. 0.52%
- B. 0.01%
- C. 0.99%
- D. 0.10%
Correct Answer: A
Rationale: The relative error is calculated using the formula: (|Measured Value - True Value| / True Value) * 100%. Substituting the values given, we have (|36 - 75| / 75) * 100% = (39 / 75) * 100% ≈ 0.52 * 100% = 0.52%. Therefore, the relative error in measurement is approximately 0.52%. Choice A is correct because it reflects this calculation. Choice B is incorrect as it represents a lower relative error than the actual value obtained. Choice C is incorrect as it overestimates the relative error. Choice D is incorrect as it underestimates the relative error.
You may also like to solve these questions
Solve the following: 4 x 7 + (25 - 21)²
- A. 512
- B. 36
- C. 44
- D. 22
Correct Answer: B
Rationale: First, solve the expression inside the parentheses:
25
−
21
=
4
25−21=4
Then, square the result from the parentheses:
4
2
=
16
4
2
=16
Perform the multiplication:
4
7
=
28
47=28
Finally, add the results:
28
+
16
=
44
28+16=44
Which of the following numbers is the largest?
- A. 0.45
- B. 0.096
- C. 0.3
- D. 0.313
Correct Answer: A
Rationale: Among the provided options, 0.45 is the largest number. To determine the largest number, compare the decimal values directly. 0.45 is greater than 0.313, 0.3, and 0.096. Therefore, 0.45 is the correct answer. Choice B (0.096) is the smallest as it has the lowest decimal value. Choice C (0.3) is greater than 0.096 but smaller than both 0.313 and 0.45. Choice D (0.313) is greater than 0.3 and 0.096 but smaller than 0.45, making it incorrect.
How much did he save from the original price?
- A. $170
- B. $212.50
- C. $105.75
- D. $200
Correct Answer: B
Rationale: To calculate the amount saved from the original price, you need to subtract the discounted price from the original price. The formula is: Original price - Discounted price = Amount saved. In this case, the original price was $850, and the discounted price was $637.50. Therefore, $850 - $637.50 = $212.50. Hence, he saved $212.50 from the original price. Choice A ($170) is incorrect as it is not the correct amount saved. Choice C ($105.75) is incorrect as it does not match the calculated savings. Choice D ($200) is incorrect as it is not the accurate amount saved based on the given prices.
What score must Dwayne get on his next math test to maintain an overall average of at least 90?
- A. 89
- B. 98
- C. 95
- D. 100
Correct Answer: B
Rationale: To maintain an overall average of at least 90, Dwayne must aim for a score of 90 on every test. If his current average is below 90, he needs to make up for it by scoring higher on upcoming tests. Choosing 98 ensures that his overall average remains at or above 90. Choice A (89) is below the desired average of 90, so it would not be sufficient. Choices C (95) and D (100) are higher than necessary to maintain an average of at least 90.
This chart indicates the number of sales of CDs, vinyl records, and MP3 downloads that occurred over the last year. Approximately what percentage of the total sales was from CDs?
- A. 55%
- B. 25%
- C. 40%
- D. 5%
Correct Answer: C
Rationale: To determine the percentage of CD sales out of the total sales, we need to consider the total sales of CDs, vinyl records, and MP3 downloads. To find the percentage of CD sales, we divide the total sales of CDs by the sum of total sales of CDs, vinyl records, and MP3 downloads, and then multiply by 100. In this case, the correct calculation shows that CDs accounted for 40% of the total sales. Choice A (55%) is incorrect as it overestimates the contribution of CDs. Choice B (25%) is incorrect as it underestimates the percentage of CD sales. Choice D (5%) is also incorrect as it severely underestimates the share of CD sales in the total sales.