Journeyman What-If Workbook: 100 Solved Variations of Your Guide's Problems

You solved the unit. Can you solve it when the conditions change? 100 worked variations (one for every unit in your guide) that change a single condition, from a 120-V heater to a 240-V one or from a 2,000 sq ft house to a 3,000 sq ft one, and show exactly how the solution shifts.