## Task 1

For the renovation of a large residential building, a total of 36 masons, roofers, and electricians are employed. One fourth of all workers are electricians. There are 16 masons on the construction site.

How many roofers and electricians are working on the construction site?
The fourth part of 36 is 9. 36 - 9 electricians - 16 masons $=11$. On the construction site, there are 9 electricians and 11 roofers.