FSOT: 500 Test Prep Study Questions

John works 40 hours in a week, at $15.00 per hour, and produces 150 widgets. Amy works 32 hours in a week, at $18.50 per hour, and produces 128 widgets. Dave works 36 hours in a week, at $17.75 per hour, and produces 141 widgets. Which employee is the most cost effective for the company in terms of widgets produced per dollar of payroll spent?