Consider a four-step serial process with processing times given in the list below. There is one machine at each step of the process, and this is a machine-paces process. Step 1: 31 minutes per unit Step 2: 15 minutes per unit Step 3: 31 minutes per unit Step 4: 25 minutes per unit.

Assuming that the process starts out empty, how long will it take (in hours) to complete a batch of 105 units? (Hours) (Round to the nearest hour)