Problem 4 (40'). During the Covid-19 outbreak in Shanghai at the beginning of 2022, Tesla set up a factory bubble to maintain operations during the city's lockdown. The carmaker now looks to return to a normal production schedule in China. Prior to the production halt in March, the plant ran on two shifts covering 24 hours (each shift covering 12 hours) and workers had two days off. Tesla plans to restore that schedule from June, bringing back staff from outside the bubble. As the city eases its curbs and the supply chains become smoother, the numbers of required staff also turn back to normal, which are outlined in the following table. Weekday Weekend Number of Required Staff 20 10 The hourly rate data are provided as in the following table: Hourly Rate Weekday Day Shift Weekday Night Shift $20 $25 Weekend Day Shift $30 Weekend Night Shift $35