This problem can be broken up into 3 parts.
Part 1: Chose 3 jobs from the 8 and then arrange the jobs among the 3 workers.
This can be done in 8!/5! ( the binomial coefficient * 3! or 8P3.
Part 2: Choose 3 jobs from the remaining 5 and then arrange them as before.
This can be done in 5P3 ways.
Part 3: The 2 remaining jobs can be distributed in 3 ways.
Now multiply the 3 results to get 8! * 3/2!