GMAT Focus EditionData InsightsMedium
A manufacturing company operates three production lines: Line A, Line B, and Line C. The company tracks the number of defects produced per batch to monitor quality. Line A produces 15 defects in a batch of 500 units. Line B produces 20 defects in a batch of 750 units. Line C produces 12 defects in a batch of 400 units. To determine which line has the best quality control, the production manager wants to compare the defect rate per 1,000 units for each line. Which line has the lowest defect rate per 1,000 units?
- ALine B
- BLines A and C have the same lowest rate
- CLine C
- DLine A
Show answer & explanationAnswer & explanation
Correct answer: D. Line A
Calculate the defect rate per 1,000 units for each line. Line A: (15/500)*1000 = 30 defects/1000 units. Line B: (20/750)*1000 = 26.67 defects/1000 units. Line C: (12/400)*1000 = 30 defects/1000 units. Line B has the lowest defect rate.
Why the other options are wrong
- A. Line B's defect rate is 26.67/1000, which is the lowest among the three lines.
- B. Lines A and C have the same rate, but it is not the lowest; Line B is lower.
- C. Line C's defect rate is 30/1000, which is not the lowest.
Defect Rate Per Thousand
Defect Rate Per Thousand (DPM) is a quality metric that measures the number of defective units found per 1,000 units produced. It normalizes defect counts for comparison across different production volumes.
- Calculated as (Number of Defects / Total Units) * 1000.
- Standardizes quality measurement.
- Lower DPM indicates better quality control.
Memory trick: Quality control: fewer defects per thousand, happier customers abound.