12. Let's pay attention to the fact that $1 \%$ of the plan for 40 parts is 0.4 parts. Next, $47 \% - 18.8$ parts. But you can't make 0.8 of a part, so the worker must make no less than 59 parts.
12. How many parts should a worker produce to exceed the plan by 40 parts by no less than $47 \%$?