Final answer:
The absolute error of the amount 400, calculated to the nearest 10, is 5 units because that is the maximum amount the reported value could vary from the actual value. It represents half of the rounding unit, which in this case is 10. Therefore, option A) 5 is the correct answer to the question.
Step-by-step explanation:
Absolute Error Explained
When an amount is calculated to the nearest 10, the absolute error is the maximum amount that the reported value could differ from the actual value. In this case, the number 400, which is rounded to the nearest 10, could vary by up to 5 units either above or below the stated amount. This is because rounding to the nearest 10 implies that any number from 395 to 404 would be rounded to 400. Consequently, the largest possible discrepancy from the true value is half the rounding unit, which is 5 in this instance.
Therefore, the correct absolute error of the amount 400, calculated to the nearest 10, would be 5 units. This would correspond to option A) 5. When dealing with measurements and calculations, understanding the concept of absolute error is crucial, as it provides a measure of how 'off' the approximate value could potentially be. For an array of numbers like 4200 and 540, where they are rounded to the nearest whole number due to lack of decimal places, the consideration of absolute error is still important to ensure accuracy in reporting and conclusions.