Specify the following queries on the COMPANY relational database schema using relational algebra

operators. Also show the result of each query as it would apply to the database state of Figure $1.$

$6$ pts per problem $(4$ pts for relational algebra query and $2$ pts for resulting relation$)$

$1)$ Retrieve the first and last names of employees that work in department $1$ or department $5.$

$2)$ Retrieve the names of all departments with a location in $$Houston$.$

$3)$ Retrieve the SSNs of all employees that work more than $20$ hours per week on project number $30.$

$4)$ Retrieve the first and last names of employees in department $4$ who work more than $15$ hours per

week on the 'Newbenefits' project.

$5)$ Retrieve the first and last names of employees that are directly supervised by $$James Borg$.$

$6)$ For each project, list the project name and the number of employees that work on the project.

$7)$ Retrieve the SSNs and first names of employees who work on every project.

$8)$ For each department, retrieve the department name, and the average salary of employees working

in that department