A company must complete three jobs. The work was executed on four machines. The processing time in minutes required for each machine is:

A job can be processed on machine

when finished processing the

.
A machine can not process two jobs at once, and once that is processing a job, you must finish before starting another.
This is to minimize the time required to execute all jobs.
Considering different elsewhere: to minimize the amount of time needed to complete the three papers.
Formulating the problem in both cases.