ACT (Enhanced)MathematicsMedium
A quality control manager is inspecting a batch of 500 items. The number of defective items (d) found is modeled by the linear equation d = 0.08n + 5, where n is the number of items inspected. What percentage of the first 100 items inspected are expected to be defective?
- A5%
- B13%
- C8%
- D10%
Show answer & explanationAnswer & explanation
Correct answer: B. 13%
First, calculate the expected number of defective items when n=100 using the given linear model. Then, divide this number by the total items inspected (100) and multiply by 100 to get the percentage.
Why the other options are wrong
- A. Incorrect. This is the constant term, representing initial defects or a baseline.
- C. Incorrect. This only accounts for the slope (0.08), ignoring the constant term (+5).
- D. Incorrect. This would be 10 defective items, possibly by miscalculation or misinterpreting the slope.
Percentage from Linear Model
To find the percentage of a quantity from a linear model, first calculate the quantity using the model, then divide by the total and multiply by 100%.
- Evaluate the linear model for the given input.
- Divide the output by the total number of items.
- Multiply the result by 100 to express as a percentage.
Memory trick: Follow the 'Linear Path' to 'Calculate' and then 'Percent-age'.