Determine the maximum contribution that can be made to a Keogh plan in each of the following cases. In all instances, the individual is self$-$employed, and the self$-$employment tax reduction has already been taken.

Self$-$employment income of $$58,000.$

Self$-$employment income of $$58,000$ and wage income of $$30,000.$

Self$-$employment income of $$125,000.$

Self$-$employment income of $$295,000.$