Answer:

Explanation:
If they are working alone
Jim does of the job in 1 hour=
of work
John does of the job in 1 hour=
of work
Let x be the number of hours to do the job if they work together.
Thus, each hour, they do
of the job when they work together.
According to the question,


∴ The number of hours to do the job if they work together=
