It takes 10 workers to produce 39 parts in a month in that same time a machine can take 6 parts and produce 1 products which sell for $100 each. If you want to make $1000 worth of sells, how many workers are needed?

Answer 1

This isn't any chemistry I've seen.
You want to make $1000 in sales (Is that in 1 month?). At $100 each you must sell 10 to get the $1000.
The machine needs 6 parts for a product so you must have 10*6 = 60 parts.
10 workers can make 39 parts in a month so you need 60 parts x (10 workers/39 parts) = 15.38. Since you can't get a worker into 0.38 parts, it would take 16 whole workers. Check my thinking.