Assume we have a system with a single-core CPU. Multiple jobs can run in parallel (multiprogramming) and finish faster than if they had run sequentially. Suppose that two jobs, each needing 20 minutes of CPU time, start simultaneously. How long will the last one take to complete if they run sequentially

40 minutes

Explanation:

The CPU is the brain of the computer system. It executes all the computing tasks and controls hardware operation. A CPU can have a single core or a multi-core, and can execute processes sequentially or in parallel.

Parallel computing executes multiple processes in parallel and at the same time, while sequential computing executes processes one at a time.

When two processes to be executed are sent to a single core sequential CPU, and if the processing for one process is 20 minutes, it will take the second task another 20 minutes, giving a total of 40 minutes to execute both processes.