Drone Worid must maintain and improve operating results tor its products. From the information in Part II where the variable costs increased by $3. How many units will have to be sold to earn the same net income of $562.000 Drone Worid must maintain and improve operating results tor its products. From the information in Part II where the variable costs increased by $3. How many units will have to be sold to earn the same net income of $562.000