When there are few other users, the task is large, and the hardware is fast, time-sharing makes sense since the mainframe has more computing power than a personal computer and that full computing power can be brought to bear on the user’s problem. Using a time-sharing system would also be appropriate if that system has expensive resources (e.g., a color laser printer) that are not available on the personal computer. Finally, if the user needs to “run” multiple tasks simultaneously, the time-sharing system would also be most appropriate, as most personal computer operating systems (with the exception of Linux) don’t support multiprocessing very well. (A personal computer, in contrast, would be better when the job is small enough to be reasonably executed on it, and when the machine’s performance is sufficient to execute the program to the user’s satisfaction.) Note that this question asks why “a” user (i.e., a single user) would be better off… It does not ask about multiple users.
